Momentum And Collisions

Physics G
Unit 6 – Momentum
Internet Lab – Momentum and Collisions
Name:

Date:

Period:

Website: http://phet.colorado.edu/
Play with the Sims  Physics Motion  Collision Lab

Introduction:
When objects move, they have momentum. Momentum, p, is the product of an object’s mass (kg) and its velocity (m/s). The unit for momentum, p, is kg·m/s. During a collision objects transfer momentum to each other, resulting in different motions than before the collision. In this activity you will study the motion colliding objects.

ELASTIC Collisions

1. What defines a collision as being elastic?

2. Simulate the four elastic collisions below. Complete the table using math formulas and the simulation.

BEFORE COLLISION

ptotal
AFTER COLLISION
#
m1 m2 v1 v2 v1 v2 1
2.0 kg
2.0 kg
1.5 m/s

0 kg·m/s

2
2.5 kg
5.0 kg

-1.0 m/s
0 kg·m/s

3
3.0 kg
6.0 kg
2.0 m/s
0.0 m/s

4
6.0 kg

2.0 m/s
-1.0 m/s
8.0 kg·m/s

3. Two objects with the same mass move toward each other with the same speed and experience an elastic collision. Compare the final velocities of each object to their initial velocities.

4. A less-massive moving object has an elastic collision with a more-massive object that is not moving. Compare the initial velocity (speed and direction) of the less-massive object to its final velocity.

INELASTIC Collisions

5. What defines a collision as being inelastic?

6. Simulate the four inelastic collisions below. Complete the table using math formulas and the simulation.

BEFORE COLLISION

ptotal
AFTER COLLISION
#
m1 m2 v1 v2 v1 and v2
1
2.0 kg
2.0 kg
1.5 m/s
0

2
3.0 kg
6.0 kg
1.5 m/s
-0.75 m/s

3
1.5 kg
5.0 kg
2.0 m/s
0.2 m/s

4
10.0 kg

2.0 m/s
-1.0 m/s
10.0 kg·m/s

7. Two objects moving toward each other with different momentums experience an inelastic collision. In which direction will both objects travel after the collision?

8. A less-massive object is moving in the same direction as a more-massive object, but with a