Description
Linear Momentum in Collisions
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Goal: To investigate the Law of Conservation of Linear Momentum in collisions.
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Simulation Used: Collision Lab from the PhET at the University of Colorado.
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Preliminary Settings.
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- Open the simulation Collision Lab.
- From the menu on the right, select: Show Values
- In the yellow window below, click on “More Data”
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Activity 1: Elastic Collisions in one dimension. Ball 2 is initially at rest.
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|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
V (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
0.50 |
1.20 |
|||
|
2 |
0.50 |
0 |
|||
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|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
1.50 |
0.90 |
|||
|
2 |
0.50 |
0 |
|||
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|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
0.50 |
1.40 |
|||
|
2 |
1.50 |
0 |
|||
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Question: Is the momentum conserved? Bottom of Form
Top of Form Bottom of Form Top of Form
Question: Is the kinetic energy conserved?
Bottom of Form Top of Form Bottom of Form
Activity 2: Elastic Collisions in one dimension. Balls 1 and 2 initially moving in the same direction.Top of Form
|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
0.50 |
0.80 |
|||
|
2 |
0.50 |
0.30 |
|||
|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
1.50 |
1.20 |
|||
|
2 |
0.50 |
0.50 |
|||
|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
0.50 |
1.20 |
|||
|
2 |
1.50 |
0.30 |
|||
Bottom of Form Top of Form Bottom of Form Top of Form
Question: Is the momentum conserved?
Question: Is the kinetic energy conserved?
Bottom of Form
Activity 3: Elastic Collisions in one dimension. Balls 1 and 2 initially moving in the opposite direction. Note that when Ball 2 moves opposite to Ball 1, its velocity and momentum are negative.
|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
0.50 |
1.20 |
|||
|
2 |
0.50 |
– 0.30 |
|||
|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
1.50 |
1.20 |
|||
|
2 |
0.50 |
-0.70 |
|||
|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
0.50 |
1.20 |
|||
|
2 |
1.50 |
-1.20 |
|||
Question: Is the momentum conserved?
Question: Is the kinetic energy conserved?
Bottom of Form
Activity 4: Inelastic Collisions. On the menu to the left, slide the indicator all the way to the left to ensure perfectly inelastic collision.
|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
0.50 |
1.20 |
|||
|
2 |
0.50 |
0 |
|||
|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
1.50 |
1.20 |
|||
|
2 |
0.50 |
-0.20 |
|||
|
Ball |
Mass (kg) |
Before the Collision |
After the Collision |
||
|
v (m/s) |
Momentum (kg.m/s) |
v (m/s) |
Momentum (kg.m/s) |
||
|
1 |
0.50 |
1.20 |
|||
|
2 |
1.50 |
-1.80 |
|||
Bottom of Form Top of Form Bottom of Form Top of Form
Question: Is the momentum conserved?
Question: Is the kinetic energy conserved?
Acknowledgements. Tatiana Stantcheva, Northern Virginia community College. The Java Applet comes from the PhET Interactive Simulations at the University of Colorado, Boulder. Some activities are based on the “Laboratory Manual, Physics 231 – 232” by Walter Wimbush, Northern Virginia Community College, 2008.
