1. Lectures by James L. Pazun 8 Momentum

2. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Goals for Chapter 8 To study momentum. To understand conservation of momentum. To study momentum changes during collisions. To add time and study impulse. To understand center of mass and how forces act on the c.o.m. To apply momentum to rocket propulsion.

3. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Momentum is a vector quantity. – Figure 8.1

4. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Momentum can cause injury ( a concussion) This is a frame of reference problem just like a passenger in a car. When the brain and skull are moving at the same velocity, there is no problem. If the skull changes abruptly the brain does not, there is a possibility of an injury.

5. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Analysis of a collision – Figure 8.2 Refer to the worked example on page 234.

6. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Momentum is conserved. – Figure 8.3 Astronauts provide excellent examples of momentum transfer.

7. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Scoring a “strike” is many momentum transfers at once.

8. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley An astronaut rescue - Example 8.2 Refer to the worked example on page 237.

9. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Rifle recoil – Example 8.3 Refer to the worked example on pages 237 and 238.

10. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Head-on collision – Example 8.4 Refer to the worked problem on page 238.

11. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Collisions on a horizontal plane – Figure 8.7 Refer to worked example on page 239.

12. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley An explosion considered backward in time – Figure 8.8 Refer to the worked example on page 239.

13. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Particles don’t separate – Figures 8.9 and 8.10 Allows us to draw the distinction between elastic collisions and inelastic collisions.

14. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Sum O momentum? We can even find physics in unexpected places.

15. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Energy in an inelastic collision – Figure 8.11 Refer to the worked example on page 241.

16. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley We may do this experiment – Figure 8.12 Air tracks allow controlled linear collisions. Refer to worked example on page 241.

17. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley The ballistic pendulum – Figure 8.13 Often done with a.22 in lab before firearms were forbidden on campus.

18. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Different masses – Figure 8.15 Incoming and outgoing velocities are very mass dependant. Refer to worked example on page 241.

19. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Different masses – Figure 8.15 Incoming and outgoing velocities are very mass dependant. Refer to worked example on page 244.

20. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Billiards? – Figure 8.16 Different situations depending on the nature of the strike

21. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley A solved air track problem – Figure 8.16 See the example on page 245.

22. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Off center collisions – Example 8.11 Difficult is the adjective that comes to mind. Refer to page 247 in your text.

23. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Impulse, duration of the impact – Figure 8.21 Again, different situations depending on the nature of the strike Refer to worked example 8.12

24. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Everything acts on the center of mass – Figure 8.25 Refer to the worked example on page 252.

25. Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley Rocket propulsion – Figure 8.28 Momentum changes themselves are altered as the projectile uses fuel or explodes. Refer to example 8.15