Linear Momentum in Collisions
Goal: To investigate the Law of Conservation of Linear Momentum in collisions
Simulation Used: Collision Lab from the PhET at the University of Colorado.
Theory
Preliminary Settings.
- Open the simulation Collision Lab.
- From the menu on the right, select: Show Values
- In the yellow window below, click on “More Data”
Activity 1: Elastic Collisions: Ball 2 is initially at rest.
On the menu to the right, slide the indicator all the way to the right for a perfectly elastic collision.
For the given masses and initial speeds of the two balls, determine the velocity and momentum after the collision.
Run 1.
| Ball | Mass (kg) | Before the Collision | After the Collision | ||
| v (m/s) | P=mv (kg.m/s) | v (m/s) | P=mv (kg.m/s) | ||
| Ball 1 | 0.50 | 1.20 | |||
| Ball 2 | 0.50 | 0 | |||
Run 2.
| Ball | Mass (kg) | Before the Collision | After the Collision | ||
| v (m/s) | P=mv (kg.m/s) | v (m/s) | P=mv (kg.m/s) | ||
| Ball 1 | 1.5 | 0.9 | |||
| Ball 2 | 0.50 | 0 | |||
Run 3.
| Ball | Mass (kg) | Before the Collision | After the Collision | ||
| v (m/s) | P=mv (kg.m/s) | v (m/s) | P=mv (kg.m/s) | ||
| Ball 1 | 0.50 | 1.4 | |||
| Ball 2 | 1.5 | 0 | |||
Question: Is the momentum conserved for each run?
Question: Is the energy conserved for each run?
Activity 2: Elastic Collisions: Balls 1 and 2 initially moving in the same direction.
Ball 1 and Ball 2 initially moving in the same directions
Question: Is the energy conserved?
Activity 3: Elastic Collisions: 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!
Run 1.
| Ball | Mass (kg) | Before the Collision | After the Collision | ||
| v (m/s) | P=mv (kg.m/s) | v (m/s) | P=mv (kg.m/s) | ||
| Ball 1 | 0.50 | 1.20 | |||
| Ball 2 | 0.50 | -0.30 | |||
Question. Is the momentum conserved?
Question: Is the energy conserved?
Activity 3: Inelastic Collisions
On the menu to the left, slide the indicator all the way to the left to ensure perfectly inelastic collisions
Run 1.
| Ball | Mass (kg) | Before the Collision | After the Collision | ||
| v (m/s) | P=mv (kg.m/s) | v (m/s) | P=mv (kg.m/s) | ||
| Ball 1 | 0.50 | 1.20 | |||
| Ball 2 | 0.50 | 0 | |||
Question. Is the momentum conserved?
Question: Is the energy conserved?