1. Day 49, Wednesday, 4 Nov., 2015 Explosions and Collisions Explosions Collisions

2. Closed and Isolated System Closed doesn’t gain or lose mass Isolated system net external forces = 0

3. Conservation of Momentum P a1 + P a2 = P b1 + P b2

4. Explosions Initial momentum is 0 P a1 + P a2 = P b1 + P b2 = 0

5. Collisions Elastic collision is one in which both kinetic energy and momentum are conserved unlike in inelastic collision in which only momentum is conserved. Elastic collisions – Collisions where the objects bounce off of each other (with no loss of kinetic energy) Inelastic collisions – Collisions where the objects stick together

6. Elastic Collision, same direction, (bounce) Before After

7. Elastic Collision, opposite direction, (bounce) Before After

8. Inelastic Collision (stick) Before After

9. 2 Dimensional Collisions Equal momentum before and after means the sum of all the parallel vector components remains the same. Equal momentum means the sum of all the perpendicular vector components equals 0.

10. 2 Dimensional Collisions Ball 1 strikes ball 2 and they bounce off in different directions

11. Credits Inelastic Collision, Truck and Car http://www.physicsclassroom.com/mmedia /momentum/treci.gif 2 D collision http://images.tutorvista.com/content/work- energy-power/oblique-collision.jpeg