1. Momentum

2. The p = m = mass v = velocity Unit: Vector Direction of momentum is determined by the direction of the

3. Momentum Newton’s 2 nd Law of Motion in terms of momentum Net External Force = time rate of change of External to the system

4. Momentum

5. Impulse I = F= force ∆t = change in time

6. Impulse - Problems Find the change in momentum 2 kg 5 m/s 3 m/s +- If ∆t = 0.020 s, find the average force the wall exerts on the ball

7. Momentum If no external unbalanced forces, so Conservation of momentum for a system w/ no external in forces

8. Examples 5 kg10 kg Before 5 kg10 kg After

9. Examples 5 kg10 kg Before 5 kg 10 kg After

10. Examples 5 kg 10 kg After 5 kg10 kg Before

11. Examples 5 kg10 kg Before 5 kg10 kg After

12. Types of Collisions Elastic Collisions – Kinetic energy is KE i = KE f Inelastic collision – Some kinetic energy is lost Typically lost to friction, sound, deformation, etc. Most collisions in “real life”

13. Types of Collisions How can you determine the type of collision? Yes Elastic No KE i > KE f Inelastic NOTE: As long as, momentum is conserved in every type of collision

14. Examples m a = 4 kg Before m b = 6 kg After m a = 4 kg m b = 6 kg Is it Elastic or Inelastic?

15. Skills Needed for Test Calculate the momentum of an object Determine and understand Impulse/ Δ P Understand and apply the conservation of momentum (P Total, i = P Total, f ) to various situations/collisions Determine and verify whether a collision is elastic or inelastic Understand collisions in 1 & 2 dimensions An understanding of previous topics (conservation of energy, motion, etc.)