Collisions Ph ET Activity PDF

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This was a phet I completed in class....

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9CP Collisions PhET Activity Click here to access the PhET: http://phet.colorado.edu/sims/collision-lab/collision-lab_en.html. Part 1: Setup 1. 2. 3. 4.

Click on the “Advanced” tab. Play around with the PhET for a few minutes to familiarize yourself with it. In the box on the right-hand side, click “1 Dimension,” “Velocity Vectors” and “Show Values.” In the box on the bottom of the screen, you can set the mass of each ball. Start by setting each ball to 5kg. 5. By clicking and dragging the velocity vectors, you can change the initial velocity of each ball. Start by setting Ball 1 to 1m/s and Ball 2 to 0m/s. 6. Find the elasticity box above the red “Reset all” tab. Notice how you can move it between 0% and 100%. In this PhET you will investigate what “elasticity” means.

Part 2: Intro Experiment 1. Start with the values shown in the table below. Before doing anything with the PhET, calculate the initial momentum of Ball 1 and Ball 2, and add them together to get the total initial momentum. Mass Mass (Ball 1) (Ball 2) 5kg 5kg

Vi (Ball 1) 1m/s

Vi Pi (Ball 1) (Ball 2) 0m/s 5kg*m/s

Pi (Ball 2)

Total Pi

Elasticity

0kg*m/s

5kg*m/s

100%

2. Predict verbally to a partner: When you roll ball 1 into ball 2 with the elasticity set at 100%, what will happen to the speed of each ball after the collision? Try it! Did the result agree with your prediction? What happened to the total momentum of the system? (Explain in words.) Answer: The total momentum stays the same, it just the balls 2 now has the momentum that ball 1 had. I thought that both balls were going to move and both move, and the first ball was going to have more velocity than the other ball. 3. Write down the final velocity of each ball. Calculate final momentum of the two balls. Then find the change in momentum by subtracting the total initial momentum from the total final momentum. What do you notice? Write your answer below. Vf (Ball 1) 0m/s

Vf (Ball 2) 1m/s

Pf (Ball 1)

Pf (Ball 2)

Total Pf

0kg*m/s

5kg*m/s

5kg*m/s

Change in P (Pf – Pi) 0kg*m/s

Answer: It had all stayed the same, the ball didn’t really lose any momentum, it was just transferred through two balls. 4. Hit the restart button. Change to the values below and calculate the initial momentum of each ball. Mass Mass (Ball 1) (Ball 2) 10kg 5kg

Vi (Ball 1) 1m/s

Vi Pi (Ball 1) (Ball 2) 0m/s 10kg*m/s

Pi (Ball 2)

Total Pi

Elasticity

0kg*m/s

10kg*m/s

100%

5. Predict verbally to a partner: When you roll ball 1 into ball 2 with the elasticity set at 100%, what will happen to the speed of each ball after the collision? Try it! Did the result agree with your prediction? What happened to the total momentum of the system? (Explain in words.) Answer: Both balls started to move when the balls were hit. I thought it was going to be very similar to the other situation and that all of the velocity would be transferred. But, when ball 1 hit ball 2, the balls both started to move, but ball two did move a lot faster than ball 1. 6. Write down the final velocity of each ball. Calculate final momentum of the two balls. Then find the change in momentum by subtracting the total initial momentum from the total final momentum. What do you notice? Write your answer below. Vf (Ball 1) 0.33m/s

Vf (Ball 2) 1.33m/s

Pf (Ball 1)

Pf (Ball 2)

Total Pf

3.33kg*m/s

6.67kg*/s

10kg*m/s

Change in P (Pf – Pi) 5kg*m/s

Answer: The total momentum is now half the amount that the initial momentum was. 7. Hit the restart button. Leave all values as they were before, except change the elasticity to 0%. Calculate the initial momentum of each ball. Mass Mass (Ball 1) (Ball 2) 10kg 5kg

Vi (Ball 1) 1m/s

Vi Pi (Ball 1) (Ball 2) 0m/s 10.04kg*m/ s

Pi (Ball 2)

Total Pi

Elasticity

0kg*m/s

10.04kg*m /s

0%

8. Predict verbally to a partner: When you roll ball 1 into ball 2 with the elasticity set at 0%, what will happen to the speed of each ball after the collision? Try it! Did the result agree with your prediction? What happened to the total momentum of the system? (Explain in words.) Answer: The results agreed with my prediction, I thought that both balls would move at the same speed and the same time, since there was no elasticity. 9. Write down the final velocity of each ball. Calculate final momentum of the two balls. Then find the change in momentum by subtracting the total initial momentum from the total final momentum. What do you notice? Write your answer below. Vf (Ball 1) 0.67m/s

Vf (Ball 2) 0.67m/s

Pf (Ball 1)

Pf (Ball 2)

Total Pf

6.69kg*m/s

3.35kg*m/s

10.04kg*m/s

Change in P (Pf – Pi) 0kg*m/s

Answer: I noticed that for the initial is the same as the final. Also, since the mass is half of ball two the momentum is around half of ball 1. 10. What do you think “elasticity” means in relation to momentum? Write your answer below. Answer: I think that elasticity means that it shows how much a ball would move after being hit. When there was 100% elasticity, the one ball bounced a lot, while the other ball only bounced a little bit when they were different weights. But, when the elasticity was turned off the balls moved at the same pace.

Part 3: Advanced Experiment Set your own mass, initial velocities, and elasticity. Think about what will happen to the total initial and total final momentum. Try it out with the PhET and see what happens. Do this with three different combinations of numbers. Show all work below. Combination 1: Mass Mass (Ball 1) (Ball 2) 25kg 35kg

Vf (Ball 1) 2.30m/s

Vi (Ball 1) 5m/s

Vf (Ball 2) 4.43m/s

Vi (Ball 2) 2.5m/s

Pi (Ball 1)

Pi (Ball 2)

Total Pi

Elasticity

125.09kg* m/s

87.39kg*m/s

212.48kg* m/s

85%

Pf (Ball 1)

Pf (Ball 2)

Total Pf

57.46kg*m/s

155.02kg*m/s

212.48kg*m/s

Change in P (Pf – Pi) 0kg*m/s

Combination 2: Mass Mass (Ball 1) (Ball 2) 0kg 15kg

Vf (Ball 1) 4.40m/s

Vi (Ball 1) 8m/s

Vf (Ball 2) 5m/s

Vi Pi (Ball 1) (Ball 2) 5m/s 0kg*m/s

Pi (Ball 2)

Total Pi

Elasticity

75kg*m/s

75kg*m/s

20%

Pf (Ball 1)

Pf (Ball 2)

Total Pf

0kg*m/s

75.05kg*m/s

75.05kg*m/s

Change in P (Pf – Pi) 0.5kg*m/s

Combination 3: Mass Mass (Ball 1) (Ball 2) 10kg 15kg

Vf (Ball 1) 2m/s

Vi (Ball 1) 2m/s

Vf (Ball 2) 5m/s

Vi Pi (Ball 1) (Ball 2) 5m/s 20kg*m/s

Pi (Ball 2)

Total Pi

Elasticity

75.05kg*m/s

95.05kg*m /s

25%

Pf (Ball 1)

Pf (Ball 2)

Total Pf

20kg*m/s

75.05kg*m/s

95.05kg*m/s

Change in P (Pf – Pi) 0kg*m/s...