1. Linear Momentum

2. 5-1 Linear Momentum

3. Linear Momentum, p – defined as mass x velocity The unit is kg·m/s A quantity used in collisions So a small object with a large velocity could have the same momentum as a large object with a small velocity 9-1 Linear Momentum

4. 5.2 Momentum and Newton’s Second Law

5. Newton’s Second Law is This is only true for objects with a constant mass The original form of the equation was This statement is true even if the mass varies 5.2 Momentum and Newton’s Second Law

6. 5.3 Impulse

7. A baseball player hits a pitch Bat delivers an impulse We actually only consider average force Impulse is define as 5.3 Impulse

8. An increase in time produces a decreases in force A decrease in time produces an increase in force 5.3 Impulse Airbag

9. 5.4 Conservation of Linear Momentum

10. If no net external force is applied to a system Then momentum is conserved 5.4 Conservation of Linear Momentum

11. External Forces will result in a change in momentum, so no conservation 1.Force added in 2.Force removed 5.4 Conservation of Linear Momentum Shuttle Launch

12. 5.5 Inelastic Collisions

13. Inelastic collision – momentum is conserved, but energy is lost Momentum is conserved 5.5 Inelastic Collisions

14. Completely (or perfectly) Inelastic collision – two objects collide and stick together 5.5 Inelastic Collisions

15. Example: On a touchdown attempt, a 95 kg running back runs toward the end zone at 3.75 m/s. A 111kg linebacker moving at 4.10 m/s meets the runner in a head on collision. If the two players stick together what is their velocity immediately after the collision? 5.5 Inelastic Collisions

16. If the collision occurs in two dimensions We need to consider the x and y axis separately 5.5 Inelastic Collisions

17. Then we use vector addition to calculate the magnitude and velocity. 5.5 Inelastic Collisions

18. Example: A 950kg car traveling east at 16m/s collides with a 1300 kg car traveling north at 21 m/s. If the collision is completely inelastic, what is the magnitude and direction of the cars’ velocity after the collision? 5.5 Inelastic Collisions

19. 5.6 Elastic Collisions

20. Elastic collision – two objects collide and bounce apart Elastic Collisions Momentum is conserved Kinetic energy is conserved too 5.5 Elastic Collisions

21. A 10 kg car moving at 2 m/s runs into a 5 kg car that is parked. What is the velocity of each car after the collision? 5.5 Elastic Collisions

22. A 10 kg car moving at 2 m/s runs into a 5 kg car that is parked. What is the velocity of each car after the collision? 5.5 Elastic Collisions

23. A 10 kg car moving at 2 m/s runs into a 5 kg car that is parked. What is the velocity of each car after the collision? 5.5 Elastic Collisions

24. A 10 kg car moving at 2 m/s runs into a 5 kg car that is parked. What is the velocity of each car after the collision? Confirm 5.5 Elastic Collisions

25. 5.7 Center of Mass

26. The point where the system can be balanced in a uniform gravitational field Uniform objects center of mass is in the center 5.7 Center of Mass Motion of CMCM Center of mass of Triangle

27. Center of mass is not always in the object Objects balance if supported at their center of mass 5.7 Center of Mass