1. Conservation of Momentum

2. Conservation of Momentum
When two objects collide, no momentum is lost or gained.
(mass x velocity)before = (mass x velocity)after
m1v1 = m2v2

3. Elastic Collision
The two object rebound without changing shape or creating heat
Example: Two billiard balls
The momentum of the two objects is switched.

4. Elastic Collision Movie

5. Sample Problem One
A 0.75 kg blue billiard ball with 4m/s velocity hits a 0.76 kg green billiard ball at rest. The balls retain their shape and no heat is created.

6. Inelastic Collisions
Any collision where the two objects are deformed or heat is generated.
These collisions still obey the laws of momentum.

7. Inelastic collision movie

8. Sample Problem:
A 0.46kg toy car traveling at 3m/s hits a stationary toy truck with a mass of 0.5kg. The collision is inelastic.
What is the mass of the car before the collision?
What is the speed of the car before the collision?

9. Sample Problem: What is the mass of the two cars after the accident?
What is the velocity of the two cars after the accident?

10. Answer What is the mass of the toy car before the collision?
0.46kg
What was the speed of the toy car before the collision?
3m/s

11. Answer What is the mass of the two cars after the accident?
0.46kg kg = 0.96kg

12. Answer: What is the velocity of both cars after the accident?
(m x v)before = (m x v)after
(0.46kg x 3m/s) = (0.96 kg x v)
1.38 kg x m/s = 0.96 kg x v
1.44m/s = v