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# Vocabulary Quiz-Friday

Vocabulary Quiz-Friday. How difficult is it to get something to change its momentum ?. P=mv. What could be manipulated in order to change the football player’s momentum?. Brick wall? Dinosaur eating football player?. P=mv.

## Vocabulary Quiz-Friday

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### Presentation Transcript

1. Vocabulary Quiz-Friday

2. How difficult is it to get something to change its momentum?

3. P=mv What could be manipulated in order to change the football player’s momentum? • Brick wall? • Dinosaur eating football player?

4. P=mv A change in momentum would mean a change in either the mass or velocity. We’ll always assume the velocity changes. What causes a change in velocity? a Force

5. Impulsealso known as change in momentum Impulse= (force)(time) = FΔt Unit is Newton-second N-s

6. Increasing Momentum

7. Increasing Momentum“Follow through” in sports • Apply the greatest force possible for the longest time possible Impulse= (force)(time) = FΔt

8. Decreasing Momentum • http://www.hailstate.com//mediaPortal/player.dbml?DB_OEM_ID=16800&id=661846&db_oem_id=16800

9. Decreasing Momentum The change in momentum may be b/c of a small force exerted over a long time The change in momentum may be b/c of a large force exerted for a short time

10. Decreasing Momentum To minimize the effect of the force on an object involved in a collision, the time must be increased.

11. Other examples that decrease the force by increasing the time • Air bags • Catching a baseball with a glove • Fighting with padded gloves v. bare fists • Rolling with a punch Padded dashboards • Packing materials • Crumple zones • New seat belts

12. Practical application Observe that the greater the time over which the collision occurs, the smaller the force acting upon the object.

13. Cradling the ball • A water balloon is thrown high into the air and successfully caught. The key to the success is to contact the balloon with outstretched arms and carry the balloon for a meter or more before finally stopping its momentum. The effect of this strategy is to extend the time over which the collision occurred and so reduce the force. • This same strategy is used by lacrosse players when catching the ball. The ball is "cradled" when caught;

14. Other examples where extending your time decreases the force • Bungee jumping • Bending your knees when you jump, not locking them • Safety nets/ giant air mattresses (during fires, circuses)

15. Impulse Activity • Monday it is supposed to be 80 degrees • Good Luck!

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