ICD-PCS Coding

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M132 Module 02 Coding Assignment

Find the correct code and explain your rationale for each case study below.

1. Case Study:

PREOPERATIVE DIAGNOSIS:

1. Gangrene right foot.

POSTOPERATIVE DIAGNOSIS:

1. Gangrene right foot.

OPERATION:

1. Right below the knee amputation.

ANESTHESIA: General LMA.

PROCEDURE: The patient was brought to the operative suite where a general LMA anesthesia was induced.

A Foley catheter was inserted. The right foot was s secluded in an isolation bag and the right lower extremity circumferentially prepped and draped in its entirety. Beginning on the right side the skin was marked with a marking pen 4 fingerbreadths below the tibial tuberosity anteriorly with a long posterior flap. The skin was incised circumferentially and the anterior musculature sharply divided exposing the tibia The tibia was cleaned with a periosteal elevator and then transected with the Stryker saw. The fibula was exposed and transected with the bone cutter and the amputation completed by sharply incising the posterior musculature. Bleeding vessels were ligated with 2-0 silk Ligature. There appeared to be adequate bleeding at this level for primary healing. The tibia was then cleaned with a bone rasp and the fibula with a rongeur. The wound was irrigated and ultimately closed without significant tension utilizing interrupted 2-0 vicryl sutures for reapproximation of the fascia and skin staples for reapproximation of the skin.

The right side was dressed with sterile gauze fluff dressings and a Kerlix roll. Estimated blood loss throughout the procedure was approximately 150 mL. The patient received one unit intraoperatively of packed cells because of preoperative anemia. She was transported in stable condition to the recovery room.

Code: Click here to enter text.

2. Case Study:

PROCEDURE: Open reduction and internal fixation of bilateral tibial plateau fractures.

INDICATIONS: This 23-year old was involved in a serious accident and sustained bilateral tibial plateau fractures

DESCRIPTION OF OPERATION: The patient was brought to the operating room and placed on the operating room table in the supine position. General anesthesia was induced, and after this both lower extremities were prepped and draped in the usual sterile fashion. Attention was first directed towards the left tibial plateau. A standard lateral procedure to reduce the lateral tibial plateau fracture was performed. After a submeniscal arthrotomy was performed, the joint was visualized via the lateral approach. The posterolateral fragments were reduced and the lateral tibial plateau was elevated, restoring the articular surface. K-wires were placed to provisionally hold this reduction. C-arm fluoroscopy was used to confirm good reduction of the joint surface. Next, a 6-hole lateral plateau locking plate from the Stryker sets was selected. This locking plate was advanced down the tibial shaft. Screws were placed to secre the plate to the bone. Four screws were placed in the distal shaft fragments and 4 locking screws in the proximal fragment. A kickstand screw was also placed in the locking mode. After all screws were placed, x-rays exhibited good reduction of the fracture, as well as good placement of all hardware. Next, the wound was thoroughly irrigated with normal saline. The meniscal arthrotomy was closed with the 0 PDS suture, including the capsule. Next, the IT band was closed with 0 Vicryl suture, followed by 2-0 Vicryl sutures for the skin and staples. Attention was then directed toward the right tibial plateau. A similar procedure was performed on the right side. Then, the lateral approach to the lateral tibial plateau was performed, exposing the fracture. The incision was approximately 4 cm on the right side. A 6-hole LISS plate was advanced down the tibial shaft. Four screws were placed in the distal fragments followed by four screws in the locking mode and proximal metaphyseal fragment. Excellent fixation was obtained. The C-arm fluoroscopy was used to confirm excellent reduction of the fracture on both the AP and lateral fluoroscopic images. Next, the wound was thoroughly irrigated and closed in layers. Sterile dressings were applied All wounds were dressed with sterile dressing and the patient was placed into knee immobilizers. The patient was then awakened from anesthesia, and transferred to recovery. The patient will be nonweightbearing for approximately three months on bilateral lower extremities. The patient will receive DVT prophylaxis during this time.

ICD-10-PCS Code: Click here to enter text.

3. Case Study:

PREOPERATIVE DIAGNOSES:

1. Pelvic pain.

2. History of previous pelvic surgery and ovarian cyst.

POSTOPERATIVE DIAGNOSES:

1. Pelvic pain.

2. History of previous pelvic surgery and ovarian cyst.

OPERATION PERFORMED: Laparoscopic adhesiolysis.

SURGEON: Susan Smith, MD

ANESTHESIA: General endotracheal.

ESTIMATED BLOOD LOSS: Less than 10 mL.

URINE OUTPUT: 70 mL.

IV FLUIDS: 750 mL.

DESCRIPTION OF OPERATION: After informed consent was obtained, the patient was taken to the operating room. She was placed in the dorsal supine position and general anesthesia was induced and prepped and draped in the usual sterile fashion. A Foley catheter was placed to gravity and speculum was placed in the posterior and anterior vagina and the cervix was grasped with a single-toothed tenaculum. A Hulka clamp was then inserted through the cervix into the uterus for uterine manipulations and the tenaculum was removed and attention was then turned to the abdomen.

A supraumbilical incision was made with a scalpel and elevated up with towel clamps. A long Veress needle was then placed and CO2 gas was used to insufflate the abdomen and pelvis. A 10-12 trocar and sleeve were then placed and confirmed via the laparoscope. The dense greater omental adhesions to the anterior abdominal wall were noted immediately. At this time, we were not able to see into the pelvic region. A second 5 mm trocar and sleeve were placed in the left mid quadrant under direct visualization. The ligature device was then placed developing a plane between the omentum and the anterior abdominal wall.

The adhesiolysis took place and it took approximately 25 minutes to release all of the omental adhesions from the anterior abdominal wall. We were then able to visualize the pelvis and a blunt probe was placed through the port. The ovary was visualized and photos were taken with no evidence of any ovarian cyst or ovarian pathology or of pelvic endometriosis. The uterus also appeared normal and the left tube and ovary were surgically absent. The appendix was easily visualized and noted to be noninflamed, normal in appearance, and there were no adhesions in the right lower quadrant. The upper abdominal exam was unremarkable. The procedure was terminated at this time. The ports were removed. CO2 gas was allowed to escape. The incisions were closed with 4-0 Vicryl suture. The Hulka clamp was removed. The vagina was noted to be hemostatic. The patient’s anesthesia was awakened from anesthesia, the Foley catheter was removed, and she was taken in stable condition to the recovery room.

ICD-10-PCS Code:

 
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Force Lab- Physics

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VPL Lab ah-Force Table 1 Rev 7/17/14

Name School ____________________________________ Date

The Force Table – Vector Addition and Resolution

“Vectors? I don’t have any vectors, I’m just a kid.” – From Flight of the Navigator

PURPOSE

 To observe how forces acting on an object add to produces a net, resultant force

 To see the relationship between the equilibrant force relates to the resultant force

 To develop skills with graphical addition of vectors and vector components

 To develop skills with analytical addition of vectors and vector components

EXPLORE THE FORCE TABLE APPARATUS; THEORY

See Video Overview at: http://virtuallabs.ket.org/physics/apparatus/04_1stequil/

 

Figure 1 – The Force Table Apparatus

Important Note: For each direction answer enter an angle between 0° and 360° with respect to the force table.

Working with vectors graphically is somewhat imprecise. You should expect to see lower precision in this lab. But working

with vectors graphically will give you a better understanding of vector addition and vector components. You can improve

your precision by using the Zoom features of the apparatus.

 

VPL Lab ah-Force Table 2 Rev 7/17/14

PROCEDURE

I. Addition of Two Dimensional Vectors

In this part you’ll add two forces to find their resultant using experimental addition, graphical addition, and analytical

addition. The two forces you’ll work with are:

F2 = .300 g N at θ2 = 320°

F4 = .180 g N at θ4 = 60°

There are two things that we should clarify about these two statements. We’ll refer to Figure 1 in the following.

 The force subscripts on forces and angles (F2, θ2) refer to the hanger numbers. For example, in Figure 1,

θ1 = 20°

 The notation for forces in this lab is a bit unusual. From the “Masses on Hangers” table we know that hanger #1 has

a 50 g, and a 200 g mass on it. The hanger’s mass is 50 g, so the total, 300 g, is shown in the box beside the hanger.

Be we want to record forces in newtons. From W = mg, we can easily calculate the weight of a 300-g mass.

W = .300 kg × 9.8 N/kg = 2.94 N

But there’s a much more convenient way of handling this. We can abbreviate this calculation to the simpler

W = .300 g N

A. Experimental Addition; The Equilibrant

By experimental addition we mean that we will actually apply the two forces to an object and measure their total, resultant

effect. We’ll do that by first finding the equilibrant, E, the force that exactly balances them. When this equilibrium is

achieved the ring will be centered. The resultant, R, is the single force that exactly balances the equilibrant. That is, either F2

and F4, or their resultant R can be used to balance the equilibrant.

Note: When adjusting the angle of a pulley to a prescribed angle, pay no attention to the string. Drag the pulley until the

color-coded pointer is at the desired setting. Another way that works well is to disable all the hangers while adjusting the

angles. When you do this, the ring is automatically centered so the strings can be used to help adjust the angle.

1. Enable pulleys 2 and 4 and disable pulleys 1 and 3 using their check boxes. A disabled pulley is greyed out. You can

drag it anywhere you like since any masses on it are inactive.

2. Drag pulleys 2 and 4 to their assigned angles θ2 and θ4. Use the purple and blue pointers of the pulley systems, not the

strings, to set the angles. You should zoom in to set the angles more precisely.

3. Add masses to hangers 2 and 4 to produce forces F2 and F4.

4. Enable pulley 3.

5. Using pulley 3, experimentally determine the equilibrant, E to just balance (cancel) F2 and F4. Do this by

adjusting the mass on the hanger and the angle until the yellow ring is approximately centered on the central

pin. You can add and remove masses to home in on it. You add masses by dragging and dropping them on a

hanger. You remove them using the Mass Total/Mass Removal tool. This tool displays the total mass on the

hanger, including the hanger’s mass. Clicking on the tool removes the top mass on the hanger.

 

MT/MR

Tool

Experimental Equilibrant, E: g N, °

6. From your value of E, what should be the resultant of F2 and F4? (Same force, opposite direction.)

Predicted Resultant, R: g N, °

7. Disable pulleys 2 and 4 and enable pulley 1. Experimentally determine the resultant by adjusting the mass on pulley 1

and its angle until it balances the equilibrant. That is, the ring should not move substantially when you change between

enabling F2 and F4, and enabling just F1.

Experimental Resultant, R: g N, °

 

 

VPL Lab ah-Force Table 3 Rev 7/17/14

B. Graphical Addition

With graphical addition you will create a scaled vector arrow to represent each force. We add vector arrows by connecting

them together tail to head in any order. Their sum is found by drawing a vector from the tail of the first to the head of the last.

Using the default 2×102 g vector scale, create vector arrows (± 3 grams) for F2, F4. For example, drag the purple vector by its

body and drop it when its tail (the square end) is near the central pin. It should snap in place.

You now want to adjust its direction and length to correspond to direction and magnitude of F2. It’s hard to do both of these

at the same time. That’s where the Resize Only and Rotate Only tools come into play. They let you first adjust the direction

and then adjust the length. Let’s do F2.

Zoom in. Drag the head (tip) of the vector arrow in the assigned direction force F2. That is, θ2. Zoom out. Click the Resize

Only check box. It’s direction is now fixed until you uncheck that box. You can now drag the head of the arrow and adjust

just its magnitude without changing its direction. The current magnitude of F2 is displayed at the top of the screen next to the

home location of that purple vector. You need to adjust its length to 310 ± 3 g. Repeat for F4 using the blue arrow.

The resultant, R, is the vector sum of F2 and F4. Add F2 and F4 graphically by dragging the body of F4 until its tail is over

the tip of F2 and releasing it. Form the resultant, R, by creating an orange vector, F1, from the tail of the first vector, F2, to

the head of the last vector, F4. (You can actually connect F2 and F4 in either order.) You can read the magnitude and

direction of R directly from the length and direction of F1. You’ll likely find some disagreement between these results and

your results from part A. This is because both methods are somewhat imprecise.

1. Graphical Resultant, R: g N, °

The equilibrant, E should be the same magnitude as R,

but in the opposite direction. Produce E with the green

vector arrow. It should be attached to the central pin and

in the direction of the force F3.

2. Graphical Equilibrant, E: g N, °

3. Draw each of the four vector arrows on Figure 2.

Vectors F2 and F4 should be shown added in their tail to

head arrangement. The E and R vectors should be shown

radiating out from the central pin.

Label each vector with its force value in g N units.

4. Take a Screenshot of the force table showing your four

force vectors. Make it large enough to include the

MT/MR text boxes displaying the mass values. Disable

pulley 1 so as to show the system in equilibrium. Save

the figure locally as “FTable_2.png”, print it out, and

paste it in the space provided.

Figure 2: Graphical Addition; Equilibrant

5. Describe what we mean by the terms resultant and equilibrant in relation to the forces acting in this experiment?

 

VPL Lab ah-Force Table 4 Rev 7/17/14

6. From your figures, which two forces, when added would

equal zero?

Circle two F2 F4 E R

7. Show this graphical addition in the space to the right. You’ll

want to offset them a bit since they would otherwise be on

top of one another.

8. Create the same arrangement somewhere on the screen on

your apparatus. Take a Screenshot, save it locally as

“FTable_3.png”, print it out, and paste it in the space

provided.

9. What three vectors, when added would equal zero?

Circle three F2 F4 E R

10. Show this graphical addition in the space to the right.

11. Create the same arrangement somewhere on the screen on

your apparatus. Take a Screenshot, save it locally as

“FTable_4.png”, print it out, and paste it in the space

provided.

 

Figure 3: Two Forces Adding to Zero

 

Figure 4: Three Forces Adding to Zero

 

12. Vector E should appear in both Figure 3 and Figure 4. Why?

 

C. Analytical addition with components

You’ve found experimentally and graphically how to add the forces F2 and F4 to produce the resultant, R. Hopefully you

found that these two methods make it very clear to you what is meant by the addition of vectors. But you also found that both

methods are pretty imprecise – sort of the stone tools version of vector addition. We can get much better results using

trigonometry.

You’ve just verified that the resultant effect of two (or more) vectors can be found by attaching them together tail to head and

drawing a new vector from the tail of the first to the head of the last. That single new vector is equivalent to the two original

vectors acting together. So the one achieves the same result as the original two. The reverse is also true. We can simplify the

process of addition of vectors if we replace each vector with a pair of vectors whose sum equals the original vector. At least if

we do it strategically.

1. Put all four vectors back at the center of the force table with their tails snapped to the central pin. Click the check box

beside the purple arrow under “Show Components.” Zoom in for a better look. The two new purple vectors are the x and

y-components of the purple vector, F2. We would call them F2x and F2y.

2. Drag the x-component, F2x and add it to the F2y. That is, connect its tail to the head of F2y. Clearly they add up to F2. But

just to be sure, drag F2x back to the center and add F2y to it. Same result.

So F2 = F2x + F2y. A

Note that this is all vector addition. We’re using bold text for our vector names to emphasize that this is not scalar

addition, which doesn’t take direction into account. F2 equals the vector sum of F2x and F2y because when we connect

the components together tail to head, the vector from the tail of the first to the head of the last is F2.

So, we can use F2 and F2x + F2y interchangeably. That’s the strategic part.

3. Turn on the blue components.

 

 

VPL Lab ah-Force Table 5 Rev 7/17/14

4. We’ll dim the main vectors. Drag the large blue dragger on the Vector Brightness tool almost all the way to the left. Only

the components will remain bright. Leaving one of them, say F2x where it is, add the other three components to it in any

order you like. This might be a good time to Hide the Table. There’s a button at the top. Feel free to hide and show the

force table as needed.

5. Notice where the head of the last component ends up. Notice how the four components add up to R! Try another order of

addition. The order doesn’t matter. So we can say,

R = F1 = F2x + F2y + F4x + F4y in any order.

Remember, this is vector addition, not scalar addition. So we’re still having to connect them together graphically to find

the resultant. We’re still using stone tools.

6. Turn the components for F1. You now have three sets of components.

7. Drag all the y-components out of the way.

8. Add F2x and F4x together.

9. How do these two vectors relate to F1x that is, Rx?

 

10. Repeat with the y-components. What similar statement can you make about the y-components?

 

11. Finally, how is R related to Rx and Rx?

 

To summarize,

Rx = F2x + F4x and Ry = F2y + F4y and R = Rx + Ry

 

Figure 5: Vector Components

We can now leave our stone tools behind and take advantage of this new formulation by using trigonometric functions and

the Pythagorean Theorem.

Here’s our task. You were previously asked to find the resultant, R of F2 and F4 graphically. You now want to find the same

result without the using the imprecise graphical methods.

Knowing F2 and θ2 we can calculate F2x and F2y analytically as follows.

F2x = F2 cos(θ2) (1)

F2y = F2 sin(θ2) (2)

We can do the same for F4. We can then find Rx and Ry using

Rx = F2x + F4x (3)

Ry = F2y + F4y (4)

R = Rx + Ry (5)

 

 

VPL Lab ah-Force Table 6 Rev 7/17/14

There’s one slight problem with Equation 5. Like Equations 3, and 4, it’s a vector equation, but in Equations 3, and 4, the

vectors are collinear, so they can be added with signs indicating direction. But since vectors Rx and Ry are perpendicular, we

have to use the Pythagorean theorem instead. So we can find the magnitude and direction of the resultant, R with the

magnitudes of R’s components.

R2 = Rx2 + Ry2 (6)

tan(θ) = Ry/Rx (7)

12. You’ve found experimentally and graphically how to add the forces F2 and F4 to produce the resultant, R. Now let’s try

analytical addition. Using the table provided, find the components of F2 and F4 and add them to find the components of

R. Use these components of R to determine the magnitude and direction of R. Note that one of the four components will

have a negative sign. The components now displayed on the force table should make it clear why.

13. Show all your calculations leading to your value for R below. Remember, a vector has both a magnitude and a direction.

A summary of the steps is provided to get you started.

x-Components y-Components

F2x = g N F2y = g N

F4x = g N F4y = g N

Rx = g N Ry = g N

R = g N, ° (State your angle between 0 and 360°.)

F2x = F2 cos(θ2) = .300 g N cos(θ2) F2y = F2 sin(θ4) = .300 g N sin(θ4)

Rx = F2x + F4x Fy = F2y + F4y R2 = Rx2 + Ry2 tan(θ) = Ry/Rx

 

II. SIMULATION OF A SLACKWIRE PROBLEM.

Let’s model a realistic system similar to what you might find in your homework. Figure 6 shows a crude figure of slackwire

walker, Elvira, making her way across the wire. She weighs 450 N. (About 100 lbs.) At a certain instant the two sides of the

rope are at the angles shown. Only friction allows her to stay in place. The gravitational force is acting to pull her down the

steeper ‘hill.’ If she was on a unicycle she’d tend to roll to the center. It’s complicated.

When friction is holding her in place the single rope acts like two separate sections of rope in this situation with different

tension forces on either side of her. To understand this it helps to imagine her at the extreme left where the left section of rope

is almost vertical and the right one is much less steep. In this case T3 is providing almost all of the vertical support, while T1

pulls her a little to the right. It helps to just try it. Attach a string between two objects in the room. Leave a little slack in it.

Now pull down at various points. You’ll feel the big frictional tug on the more vertical side and less from the more horizontal

side.

We want to explore this by letting her move along the rope.

 

 

VPL Lab ah-Force Table 7 Rev 7/17/14

Figure 6: Elvira Off-center on the Slackwire

 

A. Experimental Determination of T1 and T3

1. Preliminary prediction: Which tension do you think is greater, T1 or T3? Circle one.

First send each of your vectors “home” by clicking on each of their little houses. Then remove all the masses from your

four pulleys by activating all of them using their click boxes and then clicking in the total mass boxes beside each hanger

until they read 50.

Elvira weighs N.

We’ll let one gram represent 1 N on our force table and set our vector scale to 4×102 N. (Note the label to the left of each

vector.) We’ll picture our force table as if it were in a vertical plane with 270° downward and 90° upward. We’ll use

pulleys 1, 3, and 2 to provide our two tensions, T1 and T3, and the weight of Elvira respectively.

Disable all pulleys and set all the angles to match Figure 6. Use Zoom.

Turn pulleys 1, 3, and 2 back on.

2. Prediction: Since θ3 = 2 × θ1, do you think T3 will be about twice T1?

3. Set Elvira’s weight to the value you were assigned. If you’re assigned a weight of 450 N, use 450 g including the mass of

the hanger. So you’d add 400 g.

4. Adjust the masses on each pulley until you achieve equilibrium. It’s best to alternate adding one mass to each side in turn

until you get close to equilibrium.

5. T1 = N at 10°

6. T3 = N at 160°

How’d that prediction go (#2)? If trig functions were linear we wouldn’t need them.

7. Write a statement about the relationship between the steepness of the rope and the tension in that rope for this vertical

arrangement.

 

VPL Lab ah-Force Table 8 Rev 7/17/14

B. Graphical Check of our Results

1. Using the vector scale of 4×102 N, create

vector arrows for each force, T3, T1, and W.

Don’t forget to use the Resize Only tool

after you get the angles set.

2. Take a Screenshot, save it locally as

“FTable_7.png”, print it out, and paste it in

the space provided.

3. Draw your three vectors on Figure 7.

4. How can we graphically check to see if our

values for T1 and T3 are reasonably correct?

How are T1, T3, and W related? What would

happen if any one of them suddenly went

away? Elvira would no longer be in

.Figure 7: Elvira – Asymmetrical Vectors

 

Thus the three vectors are in equilibrium and must add to equal zero! What would that look like? The sum, resultant, of

three vectors is a vector from the tail of the first to the head of the last. If they add up to zero, then the resultant’s

magnitude would be zero which means that the tip of the final vector would lie at the tail of the first vector.

Try it in with your apparatus. Leave T1 where it is, then drag T3’s tail to T1’s head. Then drag W’s tail to the head of T3.

5. What about your new figure says (approximately) that the three forces are in equilibrium?

 

6. Draw your new figure with

the three vectors added

together on Figure 8.

7. Take a Screenshot, save it

locally as “FTable_8.png”,

print it out, and paste it in the

space provided.

 

Figure 8: Graphical Addition – Asymmetrical

 

VPL Lab ah-Force Table 9 Rev 7/17/14

C. Analytical Check of Your Results

If our three vectors add up to zero, then what about their components?

1. When you add up the x-components of all three vectors the sum should be

2. When you add up the y-components of all three vectors the sum should be

3. Test your predictions using the following table. Don’t forget the direction signs!

x-Components y-Components

F1x = N F1y = N

F3x = N F3y = N

Wx = N Wy = N

ΣFx = N ΣFy = N

4. Show your calculations of the eight values in the table in the space provided below.

 

Before we continue… Why all the tension?

Why does the tension on each side have to be so much larger than the weight actually being supported? All the extra tension

is being supplied by the x-components. Then why not just get rid of it? You’d have to move the supports right next to each

other to make both ropes vertical. That would be pretty boring and frankly nobody would pay to see such an act, even if they

tried calling it “Xtreme Urban Slackwire.”

Similarly, wih traffic lights, a huge amount of tension is required to support a fairly light traffic light. The simpler solution of

a pair of poles in the middle of the intersection wouldn’t go over much better than Xtreme Urban Slackwire.

Next time you see poles or towers supporting large electrical wires look for places where the wire has to change direction.

(South to East for example.) The support structures in straight stretches (in-line) don’t have to be really sturdy since they

have horizontal forces pulling equally in opposite directions. Thus they just have to support the weight of the wire. When the

wires have to change directions the poles at the corners have to provide these horizontal forces. Thus they’re much sturdier

and larger to give them a wider base. They often have guy wires to the ground to help provide these forces. To make things

more difficult the guy wires will be usually be very steep so they have to have a lot of extra tension in them to supply the

horizontal force components.

 

Figure 9: Power Lines – In Line and at Corners

 

 

VPL Lab ah-Force Table 10 Rev 7/17/14

III. SIMULATION OF A SYMMETRICAL SLACKWIRE PROBLEM.

In Figure 10, Elvira has reached the center of the wire. This is where she would be if she rode a unicycle and just let it take

her to the “bottom.” The angle values are just guesses. They’d be between the 10° and 20° we had before, but the actual value

would depend on the length of the wire and its elastic properties.

 

Figure 10: Elvira at the Center of the Slackwire

Without changing the masses used in part II, adjust both angles to 15°.

1. What does the symmetry of the figure suggest about how the tensions T1, and T3 should compare?

 

2. Similarly what can you say about comparative values of the x-components T1x and T3x? (Ex. Maybe T1x = 2× T3x?)

 

3. What can you say about comparative values of the y-components T1y and T3y?

 

4. Knowing that the weight being supported is 450 N, what can you say about actual values of the y-components T1y and

T3y?

 

5. T1y = T3y = N

You can now easily calculate T1 and hence T3.

6. T1 = T3 = N at 15°

Show the calculation of T1 below.

 

 

7. Change each T to as close as you can get to this amount. Does this produce equilibrium?

8. With your apparatus, create the two vector arrows to match this amount – one for T1 and one for T3. Add T1 + T3 + W

graphically. Draw or paste a copy of this graphical addition below.

 

 

VPL Lab ah-Force Table 11 Rev 7/17/14

9. Create the two vector arrows to match

this amount – one for T1 and one for

T3. Add T1 + T3 + W graphically. Draw

or paste a copy of this graphical

addition in Figure 11.

10. Take a Screenshot, save it locally as

“FTable_11.png”, print it out, and

paste it in the space provided.

You’ll notice that this figure doesn’t differ

much from the previous one. The graphical

tool we’re using is not very precise. The

same goes for “the real world.” Measuring

the tension in a heavy electrical cable or

bridge support cable is very difficult. One

good method involves whacking it with a

hammer and listening for the note it plays!

Figure 11: Graphical Addition – Symmetrical

IV. VECTOR SUBTRACTION

Here’s the scenario. We have a three-person kinder, gentler tug-o-war. The goal is to reach consensus, stalemate. Two of our

contestants are already at work.

Darryl1 = 800 N at 0°

Darryl2 = 650 N at 240°

The question is – how hard, and in what direction, must Larry3 pull to achieve equilibrium?

1. As before, empty all the hangers, and then set up pulleys 1 and 2 to represent these forces using 1 gram/1 newton.

2. Send all the vector arrows home to get a clean slate. Then create orange and purple vectors to match using the 4×102 N

for your vector scale. Attach them to the central pin.

One method of solving the problem is to add the Daryl forces to find the resultant. Larry’s force would be the equilibrant in

the other direction. Another way is to add the two Daryl forces and then draw a third force, Larry, to complete the triangle

which would leave a resultant of zero.

The following vector equation describes that method.

ΣF = Darryl1 + Darryl2 + Larry3 = 0

This is a vector equation. It means that you’ll get a resultant of zero if you connect the three vectors together tail to head. To

find the Larry vector we need to subtract the two Darryl vectors from both sides. We know how to add vectors but how do

we subtract them?

With scalar math it would look like this:

ΣWorth = Darryl1$ + Darryl2$ + Larry3$ = 0 (Yes, that’s net worth)

Larry3$ = –Darryl1$ – Darryl2$

If Darryl1$ = $800 and Darryl2 = $650, they we’d get

Larry3$ = –$800 –$650 (Note that we’re adding negatives here.)

Larry3$ = –$1450

 

 

VPL Lab ah-Force Table 12 Rev 7/17/14

Negative dollars don’t exist but we would interpret this as something like a debt. That is to make the three brothers have zero

net worth, Larry3 needs to be $1450 in debt.

With vectors it works the same way but we interpret the negatives signs as indications of direction. A pull of -50 N to the left

means a pull of 50 N to the right.

ΣF = Darryl1 + Darryl2 + Larry3 = 0

Larry3 = –Darryl1 – Darryl2

Larry3 = (–Darryl1) + (–Darryl2)

So to find Larry3 we need to create the two negative Darryl vectors and add them.

This means to draw the vector (–Darryl1) and (–Darryl2) which are the opposites of Darryl1 and Darryl2 and add them. That

is, we can subtract vectors by adding their negatives.

So if

Darryl1 = 800 N at 0°

Darryl2 = 650 N at 240°

then the negatives of these are vectors of the same lengths but in the opposite directions. Thus,

–Darryl1 = 800 N at 180°

–Darryl2 = 650 N at 60°

3. Ruining the hard work you just did, create

these two –Darryl vector arrows. (Don’t

change the mass hangers. Just the vectors.)

You’ll do this by just reversing the directions

of both the vector arrows you initially created.

Leaving the –Darryl1 vector pointing at 180°,

add the –Darryl2 vector in the usual tail to

head fashion.

Larry3 is the sum of these two. Create the

green Larry3 vector from the tail of -Darryl1

to the head of -Darryl2.

Draw these three vectors on Figure 12.

4. Take a Screenshot, save it locally as

“FTable_12.png”, print it out, and paste it in

the space provided.

Figure 12: Larry and 2 Darryls

 

5. Larry3 (graphical) = N ° (from the length and direction of your green, Larry3 vector)

Move pulley 3 to the position indicated by the direction of Larry3. You’ll want to temporarily turn off the hangers to set

the angle correctly.

Place the necessary mass on hanger three to produce the Larry3 force.

6. Larry3 (experimental) = N ° (from the mass on hanger 3 and the location of the pulley)

Ta Da! I hope this has made vectors as little bit less mystifying.

 
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NSCI 101 LAB2

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image1.emf

image1.emfUMUC NSCI 101/103

Lab 2: Types of Forces

INSTRUCTIONS:

· On your own and without assistance, complete this Lab 2 Answer Form electronically and submit it via the Assignments Folder by the date listed on your Course Schedule (under Syllabus).

· To conduct your laboratory exercises, use the Laboratory Manual that is available in the classroom. Laboratory exercises on your CD may not be updated.

· Save your Lab 2 Answer Form in the following format: LastName_Lab2 (e.g., Smith_Lab2).

· You should submit your document in a Word (.doc or .docx) or Rich Text Format (.rtf) for best compatibility.

Experiment 1: Friction

Table 1: Applied Force Required to Slide Cup

Cup Material Force Applied F1

m1 = 300 g water

 Force Applied F2

m2 = 150 g water

 F1 / FN1

 

 F2 / FN2

 
Plastic        
 

        
 

        
 

        
 

        
 

 Avg: Avg: Avg: Avg:
Styrofoam        
 

        
 

        
 

        
 

        
 

 Avg: Avg: Avg: Avg:
Paper F1

m1 = 150 g water

 F2

m1 = 100 g water

 F1 / FN1

 

 F2 / FN2

 
 

        
 

        
 

        
 

        
 

        
 

 Avg: Avg: Avg: Avg:
Surface Description        

Questions:

1. What happened to your applied force Fapp as you decreased the amount of water in the cup?

2.  Assume the mass to be exactly equal to the mass of water. Calculate the normal force (FN) for 300 g, 150 g, and 100 g. Use these values to compute the ratio of the Applied Force (Fapp) to the Normal Force (Fn). Place these values in the rightmost column of Table 1.

What do these last two columns represent? What is the ratio of the normal forces F1 / F300? Compare this to your values for F2/ F150, and F3/F100. What can you conclude about the ratio between the Force Normal and the Force Friction?

FN= mg FN (300 g) = _________kg × 9.8 m/s2 = ___________ FN (150 g) = _________kg × 9.8 m/s2 = ___________ FN (100 g) = _________kg × 9.8 m/s2 = ___________

3. Why doesn’t the normal force FN depend on the cup material?

4. Right as the cup begins to slide the applied force is equal to the force of friction—draw a free body diagram for each type of cup (a total of three diagrams). Label the force due to gravity mg, the normal force FN, and the friction force Ff, but don’t use any specific numbers. What makes this a state of equilibrium?

5. Does it take more force to slide an object across a surface if there is a high value of μ or a low one? Explain your answer

Experiment 2: Velocity and Air-Resistance

Table 2: Coffee Filter Data

Procedure 1
 

 1 Coffee Filter 2 Coffee Filters
Height of Table (m)    
Total Time (s) – Trial 1    
Total Time (s) – Trial 2    
Total Time (s) – Trial 3    
Total Time (s) – Trial 4    
Total Time (s) – Trial 5  

  
Calculated Average Speed (m/s)    
Procedure 2
Measured Height (m)    
Total Time (s) – Trial 1    
Total Time (s) – Trial 2    
Total Time (s) – Trial 3    
Total Time (s) – Trial 4    
Total Time (s) – Trial 5    
Average Time (s)    
Calculated Height (m)    

Questions:

1. Draw a FBD for the falling coffee filter. What is the net force?

2. What are we assuming by using the average velocity from Procedure 1 to estimate the height of the fall in Procedure 2?

3. Is the object actually traveling at the average speed over the duration of its fall? Where does the acceleration occur?

4. Draw the FBD for the 2-filter combination, assuming constant velocity. What is the net force?

5. How do your measured and calculated values for the height in Procedure 2 compare? If they are significantly different, explain what you think caused the difference.

6. Why do two coffee filters reach a higher velocity in free fall than one coffee filter?

7. How would the FBD differ for a round rubber ball dropped from the same height?

TYPE YOUR FULL NAME:

 
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Physics Lab

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I need some one do my physics lab reports.

 

 

Expression of the experimental results is an integral part of science. The lab report should have the following format:

  •  Cover page (10 points) – course name (PHY 132), title of the experiment, your name (prominent), section number, TA’s name, date of experiment, an abstract. An abstract (two paragraphs long) is the place where you briefly summarize the experiment and cite your main experimental results along with any associated errors and units. Write the abstract after all the other sections are completed.

The main body of the report will contain the following sections, each of which must be clearly labeled:

  • Objectives (5 points) – in one or two sentences describe the purpose of the lab. What physical quantities are you measuring? What physical principles/laws are you investigating?
  • Procedure (5 points) – this section should contain a brief description of the main steps and the significant details of the experiment.
  • Experimental data (15 points) – your data should be tabulated neatly in this section. Your tables should have clear headings and contain units. All the clearly labeled plots (Figure 1, etc.) produced during lab must be attached to the report. The scales on the figures should be chosen appropriately so that the data to be presented will cover most part of the graph paper.
  • Results (20 points) – you are required to show sample calculation of the quantities you are looking for including formulas and all derived equations used in your calculations. Provide all intermediate quantities. Show the calculation of the uncertainties using the rules of the error propagation. You may choose to type these calculations, but neatly hand write will be acceptable. Please label this page Sample Calculations and box your results. Your data sheets that contain measurements generated during the lab are not the results of the lab.
  • Discussion and analysis (25 points) – here you analyze the data, briefly summarize the basic idea of the experiment, and describe the measurements you made. State the key results with uncertainties and units. Interpret your graphs and discuss what trends were observed, what was the relationship of the variables in your experiment. An important part of any experimental result is a quantification of error in the result.  Describe what you learned from your results. The answers to any questions posed to you in the lab packet should be answered here.
  • Conclusion (5 points) – Did you meet the stated objective of the lab? You will need to supply reasoning in your answers to these questions.

Overall, the lab report should to be about 5 pages long.

Each student should write his/her own laboratory report.

Duplicating reports will result in an “E” in your final grade.

All data sheets and computer printouts generated during the lab have to be labeled Fig.1, Fig. 2, and included at the end of the lab report.

Lab report without attached data sheets and/or graphs generated in the lab will automatically get a zero score.

 
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Lab Report 1-2 Pages

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Absorption Spectra of Conjugated Dyes

Introduction

In this experiment Ultraviolet-Visible spectroscopy is used to explore the electronic structure of several conjugated polyene dyes, and the Particle-in-a-Box model is used to extract structural information. The bands for polyene dyes arise from electronic transitions involving the π- electrons along the chain of the molecule and the associated wavelength of these bands depends on the spacing of the electronic energy levels.

Conjugated polyenes, such as β-carotene, are ubiquitous pigments in nature and generally absorb light in the visible portion of the electromagnetic spectrum. These polyenes have a structure with alternating π-electron character (i.e., double bonds) in which the electrons are delocalized over the entire conjugated system. By changing the size of the conjugated system, the effective “box” length over which the electrons can move is changed. This crude model of electrons moving along a chain of carbon atoms can be successfully modeled with the Particle-in-a-Box quantum mechanical model.

*Note on wavelengths: If only changes in electronic energy accompany absorption of light, a very sharp maximum in absorption should be observed at the characteristic wavelength. Although sharp lines are observed for isolated atoms, broad absorption bands are observed for substances in liquid phases (due to accompanying vibrational and rotational transitions). In this experiment, we shall assume that the wavelength maximum (the wavelength at which the dyes absorb most strongly) is the wavelength to use in the calculations.

EXPERIMENT

1. Prepare stock solutions of the dyes with methanol as the solvent (approx. 10^-5 M)

2. Prepare dilute solutions of select dyes such that the final concentration will give an

absorbance between 0.5 and 1.0 for a 1cm path length

1. Recall Beer’s Law; A = εcb & reference the extinction coefficient

2. Please check your calculations in order to minimize the amount of solvent

3. Record spectra against a solvent reference, scanning from 400-800 nm

4. Save and print your spectra

5. Determine maximum wavelength for each dye

6. Dispose of used methanol/dye solutions in the appropriate waste container

*Safety note: The dyes being used in this experiment are toxic. Be advised and avoid getting the solutions on your skin. In addition, these dyes slowly degrade in the presence of light, so attempt to keep the solutions stored in the dark when not in use.

ADDITIONAL ANALYSIS

1. Complete the analysis questions found in the text book under experiment #34 a. Do not do the “theoretical calculations” section

2. Plot the UV-Vis absorption spectra yourself (Do NOT just include a screen shot) and label the maximum wavelength for each dye

3. Calculate the effective box length, a , for the dyes

a. Include a sample calculation

4. Include a table showing the name of the dye, total number of π-electrons, maximum wavelength, and box length

5. Compare experimental length with geometric box length xb, where x is the number of bonds in the conjugated system and b=0.139 nm (assuming uniform spacing)

a. Evaluate and tabulate the difference 6. Is the Particle-in-a-Box an appropriate description of these conjugated systems?

 
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Physic II Lab Experiment

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1. In this experiment, we are going to use the PHET Bending Light Simulation to verify Snell’s Law. Once we verify the law, we can use it with the simulation to demonstrate total internal reflection, a phenomenon important to fiber optic technology. In the last activity, we will work with the separation of colors by prisms and the creation of rainbows through a demonstration of the dependence of the index of refraction on the wavelength of light.

While completing the experiment Refraction, make sure to keep the following guiding questions in mind:

· Is the angle of refraction larger or smaller for a material with a higher index of refraction? 

· What are the applications of total internal reflection and what conditions do these applications place on the geometry of the devices.

· How the rainbows are created?

To complete the experiment you will need to:

1. Be prepared with a laboratory notebook to record your observations.

1. Click the image to open the simulation experiment.

1. Perform the experiment as described.

1. Transfer your data and results from your laboratory notebook into the lab report template provided at the end of this experiment description.

1. Submit your version of the laboratory experiment report.

In your laboratory notebook, you will collect data, make observations, and ponder the questions posed within the lab instructions.  Thus, the notebook should contain all the data collected and analysis performed, which will be invaluable to you as you write the results section of your laboratory report.  Furthermore, the notebook should contain your observations and thoughts, which will allow you to address the questions posed, both for the discussion section in the laboratory report and in helping you to participate in the online discussion included in the module.

 

M6A1 Experiment: Refraction

 

PART I – Snell’s Law

Snell’s Law contains four parameters: 2 indices of refraction and 2 ray angles. In the first portion of Activity 1, we are going to vary the index of refraction of material 2 in order to determine the effect that this parameter has on the refracted angle of the ray.

Start the PHET simulation “Bending Light”(if you haven’t done so already) by clicking on the image below.

http://phet.colorado.edu/sims/bending-light/bending-light_en.jnlp

http://phet.colorado.edu/sims/bending-light/bending-light_en.jnlp

· Select the protractor from the toolbox (see the illustration below).

· Use the red button to turn the laser on.

· Move the laser to set the angle of incidence to 50 degrees.

· Leave material 1 as air and the index of refraction as 1.00.

· Vary the index of refraction in material 2 between 1.00 to 1.60.

Record your results in your laboratory notebook. How did you break up the interval n2 = 1.00 to 1.60? Why did you choose this particular interval between data points? Use a table of indexes of refraction to find materials representative of various indexes of refraction. Look up at least 3 of their densities. In general, how does the index of refraction vary with the density of the material?

Now we are going to vary the angle.

· Select the reset button.

· Select the protractor from the toolbox.

· Use the red button to turn the laser on.

· Leave material 1 as air and the index of refraction as 1.00.

· Leave material 2 as water and the index of refraction as 1.33.

In your laboratory notebook, record the calculated angle of refraction for angles of incidence in 5 degree increments between 10 degrees and 80 degrees. Use the simulation to take data at these same angles. For each angle of incidence, find the difference between the calculated refracted angle and the measured refracted angle.

Part II – Total Internal Reflection

In your laboratory notebook, calculate, if possible, the critical angle (θcrit) for n1=1.60 and n2=1.00. Also, calculate the critical angle for n1 = 1.00 and n2 = 1.60.

· Select the protractor from the toolbox.

· Use the red button to turn the laser on.

· Set the angle of incidence to 50 degrees.

· Set the index of refraction of material 1 to 1.60.

· Set the index of refraction of material 2 to 1.00.

The light is now incident from a denser material to a less dense material. The light source is now inside a denser material than the surrounding material. As a result, the refracted ray will have a greater angle of refraction (in other words, it will be bent further from the surface normal) than the incident ray. Is there an incident angle for which the refracted ray will ever reach 90 degrees or essentially transmit no light into material 2?

Use the simulation to find this critical angle (θc) if it exists.

· Set the index of refraction of material 1 to 1.00.

· Set the index of refraction of material 2 to 1.60.

Use the simulation to find this critical angle (θc) if it exists.

In your laboratory notebook, compare your results from the simulation to the calculated predictions in your laboratory notebook.

Part III – Rainbows

In this activity, we are going to try to understand the structure of a rainbow. A rainbow is a multicolored arc in the sky caused by the reflection and refraction of light within water droplets in the atmosphere.

The most common form of a rainbow is the “primary rainbow,” or an arc that shows the familiar color spectrum, or rainbow pattern of red thorough indigo, with red being the outermost color. This rainbow is caused by light being:

1. Refracted while entering a water droplet,

2. Reflected inside on the back of the water droplet, and

3. Refracted again when leaving the water droplet.

In a “double rainbow,” a second arc is seen outside the “primary rainbow.” In the second arc, the order of colors is reversed. This second rainbow is caused by light reflecting twice inside water droplets.

· Select the tab labeled Prism Break.

· Select the circular prism.

· Use the red button to turn the laser on.

· Change the index of refraction to that of water.

· Select White Light on the laser controls.

· Select Show Reflections on the laser controls.

We are going to use the circular prism to represent the cross section of a water droplet. Position the laser and circular prism such that the laser refracts through the simulated water droplet like this.

Results and Analysis

In your laboratory notebook, write down which of the colors experience the greatest change in direction through refraction. Does this color order, indigo on top, match the order of colors seen when observing a rainbow?

Rolph, E. (unknown). Full featured double rainbow in wrangell-st. elias tational park, alaska. [Photograph]. Retrieved from http://commons.wikimedia.org/wiki/File:Double-alaskan-rainbow.jpg

How then can we account for the observed color order, red on top and indigo on the bottom? The diagram below can help.

 
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Physics “DC Circuits” Lab Report

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PHY 132 Lab Title

Name: ____________ Partners: __________, __________ Section: _____ Group #: _

TA: ____________ __/__/2017

Abstract: Write a brief summary of your report here. It shouldn’t be any longer than two paragraphs, and can be shorter if you are skilled at being precise. I’m looking for major results and conclusions.

If there are no numbers here, you are not being specific enough. If there is only a sentence or two stating the results of your measurement you are not really summarizing the report.

Experimental Data: Include all of your data here. That includes EVERYTHING you measured in class. (not necessarily just the data you put in the computer and graphed. There is probably more.) Also, it is okay to include calculated results here, including errors. This is NOT the place to do your calculations, but you can display the results here. Tables are really nice for organizing data. They are not required though. If you are not using tables, then maybe have a “subsection” for different kinds of data. For example: Part 1: Inner radius = XX cm Outer radius = XX cm Part 2: Inner radius = XX cm Outer radius = XX cm Just make it really easy to identify what you measured, what the measurement was, and DON’T FORGET UNITS! Results: This is where you will show all of your calculations. This will generally include many equations. Be sure to include all of the following:

• State the equation you are going to use. (example: F=ma) • Define the parameters. (F is the force in Newtons, m is the mass in kilograms,

and a is the acceleration in m/s^2) This could be done in many ways. You could have a list of all your parameters and their meaning at the beginning of this section; you could define each parameter as they appear in the report, or any other way that ensures that any reader could identify what all of your symbols mean.

• Explain any derivations. If an equation is given in the lab manual then you can generally just use it, but if you have to combine any equations to get the one you are using or the source of your equation is in any way unclear you should explain where it comes from.

• Actually show your calculations. Just because you wrote down the right equation doesn’t mean that you used it correctly, so if you show me the numbers you used I may catch small errors you made and take off fewer points than if you just show an equation and a result that is incorrect.

• If you have to do the same calculation many different times you can show a single sample calculation and then just list the various results, but still show at least one calculation for each different equation that you use.

• There should always be some sort of error calculations as well. That may be calculations of percent error, percent difference, or error propagations, or all of

the above, but there will always be some sort of error that you need to calculate and show.

Please do your best to organize this section in such a way that it is easy to identify

what calculation you are doing. Also, this section does not need to be typed. If it is easier for you to simply write out your calculations and then include that work here, that is okay. Please, please be sure that I will be able to read your work EASILY. Discussion:

Here you describe the purpose of the experiment, briefly summarize the basic idea, what physical principles/laws are you investigating, describe the measurements you made and analyze the data. State the key results with uncertainties and units. Interpret your graphs and discuss what trends were observed and what the relationship of the variables in your experiment was. An important part of any experimental result is the quantification of error in the result. Describe the qualitative effect of each source of errors on your results. Describe what you learned from your results. The answers to any questions posed to you in the lab packet should be included here. Here you answer questions about WHY you did the things you did. Show your understanding here. For example, why did we use the slope of your graph to calculate whatever value? For what purpose was a particular step included in the procedure? You need to have your signed data sheets and graphs attached to this report. Whether they are included where they belong in the body of the report, or simply attached here at the end. They can even be attached as separate files when you submit your report, but it is recommended you not do that if you can include them somewhere in the report. Remember, the most important part of your report is that it be CLEAR! If your TA can’t read the report, he can’t grade it.

 
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Physics: Analytical Problems

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By Saturday, August 17, @ 3pm EST

 Analytical Problems:

 The following questions ask you to solve problems involving topics we’ve covered this week.

Work each problem on paper or in Microsoft Word.

 Create a free body diagram of your work for each question, along with a step-by-step solution to the problem. In other words, I need to see all your steps.

Question 1
A car with 60 cm diameter tires is traveling at a constant speed of 100 km/hr. What is the angular velocity of the tires in rad/s?

Question 2
A 3 kg ball is traveling in a circle of radius 2 meters with a tangential velocity of 2 meters/second. Find the centripetal acceleration of the ball and the centripetal force acting on it.

Question 3
An arrow is shot at an angle such that it’s horizontal velocity is 40 m/s and it’s vertical velocity is 20 m/s. Find the horizontal distance the arrow will travel before hitting the ground.

Question 4
A bolt requires 15 Nm or torque to loosen it. How much force needs to be applied to a 20 cm long wrench to loosen the bolt? Assume the force is applied perpendicular to the handle of the wrench.

Question 5
A baseball is thrown such that it is in the air for 4 seconds and lands 100 m away. Find the initial vertical and horizontal components of the baseball’s velocity.

Attached are assignment related online lectures and textbook chapters

 
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Physics Homework Sheet

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Please Provide All solutions for the answer to these problems. I have the answer I am looking at how you came to this answer.

1. A car drives 5.0 km north, then 7.3 km east, then 6.7 km northeast, all at a constant velocity. If the car had to perform 2.6 × 106 J of work during this trip, what was the magnitude of the average frictional force on the car?

2. A spring with a spring constant of 10 N/m is stretched from equilibrium to 2.9 m. How much work is done in the process?

3. 300 J of work are required to fully drive a stake into the ground. If the average resistive force on the stake by the ground is 355 N, how long is the stake?

4. Three cars (car L, car M, and car N) are moving with the same velocity, and slam on the brakes. The most massive car is car L, and the least massive is car N. Assuming all three cars have identical tires, for which car is the amount of work done by friction in stopping it the highest?

5. Sue and Betti both ski straight down a hill, both starting from rest. Sue weighs more than Betti. Neglecting friction and wind resistance, which skier will be moving the fastest at the bottom of the hill?

6. 188 J of work are needed to stretch a spring from 1.4 m to 2.9 m from equilibrium. What is the value of the spring constant?

7. A traveler pulls on a suitcase strap at an angle 36° above the horizontal. If 325 J of work are done by the strap while moving the suitcase a horizontal distance of 15 m, what is the tension in the strap?

8. How much work must be done by frictional forces in slowing a 1000.0 kg car from 27.8 m/s to rest?

9. A 31 g bullet pierces a sand bag 24 cm thick. If the initial bullet velocity was 31 m/s and it emerged from the sandbag with 13 m/s, what is the magnitude of the friction force (assuming it to be constant) the bullet experienced while it traveled through the bag?

10. 4.00 × 105 J of work are done on a 1033 kg car while it accelerates from 10.0 m/s to some final velocity. Find this final velocity.

11. A child pulls on a wagon with a force of 75 N. If the wagon moves a total of 42 m in 3.2 min, what is the average power generated by the child, in watts?

12. A spring-loaded dart gun is used to shoot a dart straight up into the air, and the dart reaches a maximum height of 24 meters. The same dart is shot up a second time from the same gun, but this time the spring is compressed only half as far (compared to the first shot). How far up does the dart go this time (neglect friction and assume the spring obeys Hooke’s law)?

13. Three cars with identical engines and tires start from rest, and accelerate at their maximum rate. Car X is the most massive, and car Z is the least massive. Which car needs to travel the furthest distance before reaching a speed of 60 mi/h?

14. A 5.7 m massless rod is loosely pinned to a frictionless pivot at 0. A 4.0 kg ball is attached to the other end of the rod. The ball is held at A, where the rod makes a 30° angle above the horizontal, and is released. The ball-rod assembly then swings freely in a vertical circle between A and B. In the figure, the ball passes through C, where the rod makes an angle of 30° below the horizontal. The speed of the ball as it passes through C is closest to:

15. A spiral spring is compressed so as to add U units of potential energy to it.

When this spring is instead stretched two-thirds of the distance it was compressed, its remaining potential energy in the same units will be.

16. A girl throws a stone from a bridge. Consider the following ways she might throw the stone. The speed of the stone as it leaves her hand is the same in each case. Case A: Thrown straight up. Case B: Thrown straight down. Case C: Thrown out at an angle of 45° above horizontal. Case D: Thrown straight out horizontally. In which case will the speed of the stone be greatest when it hits the water below?

17. Joe and Bill throw identical balls vertically upward. Joe throws his ball with an initial speed twice as high as Bill. The maximum height of Joe’s ball will be

18. A tennis ball bounces on the floor three times. If each time it loses 23% of its energy due to heating, how high does it bounce after the third time, provided we released it 1.1 m from the floor?

19. In the absence of friction, how much work would a child do while pulling a 12 kg wagon a distance of 4.2 m with a 22 N force?

20. An engine is being used to raise a 89 kg crate vertically upward. If the power output of the engine is 1620 W, how long does it take the engine to lift the crate a vertical distance of 18.7 m? Friction in the system is negligible.

21. You carry a 7.0 kg bag of groceries 1.2 m above the ground at constant velocity across a 6.9 m room. How much work do you do on the bag in the process?

22. A child does 350 J of work while pulling a box from the ground up to his tree house with a rope. The tree house is 8.8 m above the ground. What is the mass of the box?

23. Two balls having different masses reach the same height when shot into the air from the ground.

If there is no air drag, which of the following statements must be true? (More than one statement may be true.)

24. A 1000.0 kg car experiences a net force of 9500 N while decelerating from 30.0 m/s to 17.0 m/s. How far does it travel while slowing down?

25. A sand mover at a quarry lifts 2,000 kg of sand per minute a vertical distance of 12 meters. The sand is initially at rest and is discharged at the top of the sand mover with speed 5 m/s into a loading chute. At what minimum rate must power be supplied to this machine?

26. A brick is dropped from the top of a building through the air (friction is present) to the ground below.

How does the brick’s kinetic energy (K) just before striking the ground compare with the gravitational potential energy (Ugrav) at the top of the building? Set y=0at the ground level.

27. A person stands on the edge of a cliff. She throws three identical rocks with the same speed. Rock X is thrown vertically upward, rock Y is thrown horizontally, and rock Z is thrown vertically downward. Assuming the elevation loss of the three rocks is the same (the base of the cliff is flat), which rock hits the ground with the highest speed?

28. You slam on the brakes of your car in a panic and skid a distance d on a straight and level road.

If you had been traveling twice as fast, what distance would the car have skidded under the same conditions?

29. Spring #1 has a force constant of k, and spring #2 has a force constant of 2k. Both springs are attached to the ceiling, identical weights are hooked to their ends, and the weights are allowed to stretch the springs.

The ratio of the energy stored by spring #1 to that stored by spring #2 is

30. Consider two frictionless inclined planes with the same vertical height. Plane 1 makes an angle of 25.0∘ with the horizontal, and plane 2 makes an angle of 60.0∘ with the horizontal. Mass m1 is placed at the top of plane 1, and mass m2 is placed at the top of plane 2. Both masses are released at the same time.

At the bottom, which mass is going faster?

 
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Physica LAB

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Lab – Coulomb’s Law – Phet Simulation

This activity consists of two Parts

Part one: Eclectic force versus distance. Part two: Electric forces versus charge.

This lab uses the following PHeT simulation:

Coulomb’s Law

( https://phet.colorado.edu/sims/html/coulombs-law/latest/coulombs-law_en.html )

Objectives:

1- Satisfy Coulomb’s law experimentally

2- Study the parameters that affect the electric force

3- Determine the electric constant k

Theoretical Background:

Coulomb’s Law: “The magnitude of the electric force that a particle exerts on another is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.” Mathematically, the magnitude of this electrostatic force FE acting on two charged particles (q1, q2) is expressed as:

Where r is the separation distance between the charged objects and k is a constant of proportionality, called the Coulomb constant, k = 9.0 × 109 Nm2/C2.

Part one:

In this part of the experiment we will explore the inverse square relationship between distance and force. The charges will be held constant throughout.

1. Open the simulator for the macro scale and enter the following values:

,Move the charges so that is at the 0 cm mark and is at 8.0 cm Record these values and the force value into the third row of Table 1.

Calculate r2 and 1/r2 so that the entire third row is completed.

4

Table 1

q1=……… …. q2=…… …….
r (cm) r2 (m2) 1/r2 (1/m2) FE (N)
10      
9      
8      
7      
6      
5      
4      
3      

2. Move to charges into different positions so that the rest of Table 1 can be completed.

3. Examine the values you obtained for FE. How did the force change as r increased from 3 cm to 9 cm?

4. How did the force change when the value of r was reduced by one half?

5. Using only the values from the data table, determine what the force would read if the distance were increased to 24 cm. Show your work in the space below. Do not use the formula for Coulomb’s Law to solve the problem.

Part two:

In this part of the experiment you will explore the linear relationship between force and charge, and you will use this relationship to experimentally determine Coulomb’s constant k.

 

6. Change the charge on q1 to 5c and adjust the distance between the two objects to 6 cm, record them in table 2. Set the charge on q2 to 10 c and record the corresponding value for the force between the two charges into the top row of table 2.

Table 2

q1 = 5 C r=6 cm
q2 (C) FE (N)
10  
9  
8  
7  
6  
5  
4  
3  

7. Adjust the values for q2 according to Table 2 and fill out the column for FE. Do not change the values for q1 or r.

8. Compare the values for FE when q2 is 4 c and when q2 is 8 c. Does the data support a linear relationship between charge and force? Explain.

Data Analysis

9. Graph the data from Table 2 by placing FE on the y-axis and q2 measured in coulomb s (not C) on the x-axis. Draw a line of best fit. The line should pass through the origin, so do not use a broken scale for either axis.

10. The slope of the best fit line can be used to calculate the electric constant k. Since, the equation is linear, we can compare Coulomb’s Law with the slope intercept equation:

but since b = 0 and FE and q2 are variables graphed on the y and x axes respectively:

where is the slope of your line of best fit.

From Coulomb’s Law, . Since we have two equations for FE, set the right hand sides equal to each other: . Use your slope value and solve for k. You must use standard units. Note that q2 cancels on both sides. Show your work below:Applications

11. In the figure below, 𝒒𝟏, 𝒒𝟐 and 𝒒𝟑 are point charges with 𝐪𝟏=𝟑𝟎 𝐧𝐂 , 𝒒𝟐 = -20.0 nC, and 𝐪𝟑=𝟑𝟎.𝟎 nC. The mass of each charge is 0.020 kg.

a) Determine the magnitude (positive answer) of the electromagnetic force for q1 and q2:

b) Determine the magnitude (positive answer) of the electromagnetic force for q3 and q2:

c) Calculate the total electromagnetic force on q2 due to the presence of both q1 and q3. Determine the magnitude (positive answer) of the total force.

d) Calculate the direction angle of the total force. Express the angle in positive degrees measured counter-clockwise from the positive x-axis. Assume that q2 is at the origin.

 
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