Lab 2: Collisions Laboratory
Name_____________________________________ Date_______________
Assignment Submission Directions: Download this assignment sheet and complete by answering all questions. You will
need to access the simulations website to complete the labs. When completed, save your work, and upload the
document to the Assignment Upload for graded submission. 50 points.
Items in red font require submission into a prepopulated text box shown as Click here to enter text. (Note: you do not
need to fill this one in, for directions purposes only.)
Simulation Website: https://phet.colorado.edu/sims/html/collision-lab/latest/collision-lab_all.html
Learning Goals
● Apply law of conservation of momentum to solve problems of collisions.
● Explain why energy is not conserved and varies in some collisions.
● Determine the change in mechanical energy in collisions of varying “elasticity”.
● What does “elasticity” mean?
Activity
Part A: Elastic Collisions
1. Load the simulation website and select the Advanced Tab (top of simulation screen) to configure your simulation
interface as follows:
Be sure to:
● Select Explore 1 Dimension
● Select 2 Balls
● Select Velocity
● Select Momentum
● Select Center of Mass
● Select Momentum Diagram
● Select Values
● Select Reflecting Border
● Set Elastic at 100%
● Select ‘More Data’ under the
lower data table to see Mass
and Momentum data
displayed
Experiment 1A: Elastic Collisions Predictions
2. Predict what will each object’s velocity and momentum be prior to and after collision? Enter your predictions in the
data table below. Do not click play yet.
, Lab 2: Collisions Laboratory
Table 1A: Elastic Collisions Predictions Data
m1 m2 Vx1 Px1 Vx2 Px2 Vx1 P’x1 Vx2 P’x2
Initial (Before they collide) Final (After they collide)
Enter 0.50 kg 1.50 kg 1.00 0.50 kg -0.50 -0.75 kg -1.00 -0.50 kg 0.20 0.30 kg
predictions m/s m/s m/s m/s m/s m/s m/s m/s
m=mass, v=velocity, p=momentum, 1=ball 1, 2=ball 2, x= x direction, P’ means ‘prime’ or after.
3. Click the PLAY button, then record the Actual data. Note: Use the STEP button to incrementally advance your
collision from just before to just after the balls collide.
Table 1B: Elastic Collisions Simulation Data
m1 m2 Vx1 Px1 Vx2 Px2 Vx1 P’x1 Vx2 P’x2
Initial (Before they collide) Final (After they collide)
Enter 0.50 kg 1.50 kg 1.00 0.50 kg -0.50 -0.75 kg -1.25 -0.63 kg 0.25 0.38 kg
predictions m/s m/s m/s m/s m/s m/s m/s m/s
m=mass, v=velocity, p=momentum, 1=ball 1, 2=ball 2, x= x direction, P’ means ‘prime’ or after.
4. Take your data from Table 1B and use it to complete Table 1C. Add your two initial momenta and your two final
momenta (momenta is plural for momentum).
Table 1C: Adding Momenta Data
Px P’x Total P
Ball 1 (po1) = 0.50 kg m/s + (pf1) = -0.63 kg m/s = 0.13 kg m/s
Ball 2 (po2) = -0.75 kg m/s + (pf2) = 0.38 kg m/s = 0.37 kg m/s
5. Compare the total initial and final momenta of each ball before and after the collision. How do the computed values
compare?
Name_____________________________________ Date_______________
Assignment Submission Directions: Download this assignment sheet and complete by answering all questions. You will
need to access the simulations website to complete the labs. When completed, save your work, and upload the
document to the Assignment Upload for graded submission. 50 points.
Items in red font require submission into a prepopulated text box shown as Click here to enter text. (Note: you do not
need to fill this one in, for directions purposes only.)
Simulation Website: https://phet.colorado.edu/sims/html/collision-lab/latest/collision-lab_all.html
Learning Goals
● Apply law of conservation of momentum to solve problems of collisions.
● Explain why energy is not conserved and varies in some collisions.
● Determine the change in mechanical energy in collisions of varying “elasticity”.
● What does “elasticity” mean?
Activity
Part A: Elastic Collisions
1. Load the simulation website and select the Advanced Tab (top of simulation screen) to configure your simulation
interface as follows:
Be sure to:
● Select Explore 1 Dimension
● Select 2 Balls
● Select Velocity
● Select Momentum
● Select Center of Mass
● Select Momentum Diagram
● Select Values
● Select Reflecting Border
● Set Elastic at 100%
● Select ‘More Data’ under the
lower data table to see Mass
and Momentum data
displayed
Experiment 1A: Elastic Collisions Predictions
2. Predict what will each object’s velocity and momentum be prior to and after collision? Enter your predictions in the
data table below. Do not click play yet.
, Lab 2: Collisions Laboratory
Table 1A: Elastic Collisions Predictions Data
m1 m2 Vx1 Px1 Vx2 Px2 Vx1 P’x1 Vx2 P’x2
Initial (Before they collide) Final (After they collide)
Enter 0.50 kg 1.50 kg 1.00 0.50 kg -0.50 -0.75 kg -1.00 -0.50 kg 0.20 0.30 kg
predictions m/s m/s m/s m/s m/s m/s m/s m/s
m=mass, v=velocity, p=momentum, 1=ball 1, 2=ball 2, x= x direction, P’ means ‘prime’ or after.
3. Click the PLAY button, then record the Actual data. Note: Use the STEP button to incrementally advance your
collision from just before to just after the balls collide.
Table 1B: Elastic Collisions Simulation Data
m1 m2 Vx1 Px1 Vx2 Px2 Vx1 P’x1 Vx2 P’x2
Initial (Before they collide) Final (After they collide)
Enter 0.50 kg 1.50 kg 1.00 0.50 kg -0.50 -0.75 kg -1.25 -0.63 kg 0.25 0.38 kg
predictions m/s m/s m/s m/s m/s m/s m/s m/s
m=mass, v=velocity, p=momentum, 1=ball 1, 2=ball 2, x= x direction, P’ means ‘prime’ or after.
4. Take your data from Table 1B and use it to complete Table 1C. Add your two initial momenta and your two final
momenta (momenta is plural for momentum).
Table 1C: Adding Momenta Data
Px P’x Total P
Ball 1 (po1) = 0.50 kg m/s + (pf1) = -0.63 kg m/s = 0.13 kg m/s
Ball 2 (po2) = -0.75 kg m/s + (pf2) = 0.38 kg m/s = 0.37 kg m/s
5. Compare the total initial and final momenta of each ball before and after the collision. How do the computed values
compare?
