1. Collisions SPH4U

2. Momentum vs. Energy All interactions conserve momentum. They do not necessarily conserve kinetic energy.

3. Momentum vs. Energy All interactions conserve momentum. They do not necessarily conserve kinetic energy. Obvious example: Explosions Kinetic energy before is zero. Kinetic energy after is non-zero.

4. Momentum vs. Energy All interactions conserve momentum. They do not necessarily conserve kinetic energy. Head-on collisions also do not conserve energy: the kinetic energy is transformed into work done on the car.

5. Momentum vs. Energy: Example A ball of mass 0.5 kg travelling at 10 m/s strikes a stationary box of mass 0.5 kg and stays in the box. (a)What is the speed of the ball and box? (b)What is the change in kinetic energy of the system?

6. Momentum vs. Energy: Example (a)What is the speed of the ball and box?

7. Momentum vs. Energy: Example (a)What is the speed of the ball and box?

8. Momentum vs. Energy: Example (a)What is the speed of the ball and box?

9. Momentum vs. Energy: Example (a)What is the speed of the ball and box?

10. Momentum vs. Energy: Example (b) What is the change in kinetic energy of the system?

11. Momentum vs. Energy: Example (b) What is the change in kinetic energy of the system?

12. Momentum vs. Energy: Example (b) What is the change in kinetic energy of the system?

13. Momentum vs. Energy: Example (b) What is the change in kinetic energy of the system? The system loses half of its kinetic energy. The energy will have been transformed into sound energy, thermal energy, etc.

14. Inelastic Collisions A collision in which kinetic energy is lost is called an inelastic collision.

15. Inelastic Collisions A collision in which kinetic energy is lost is called an inelastic collision. A collision in which the maximum possible energy is lost is called a completely inelastic collision.

16. Completely Inelastic Collisions The maximum possible energy loss (if no work is done on the objects) occurs when the two objects stick together after colliding.

17. More Practice “Ballistic Pendulum Activity” Textbook Questions p. 251 #10 p. 253 #6, 7