- #1

- 38

- 0

A) 4390 N

B) 10,260 N

C) 5870 N

D) 7300 N

E) 8780 N

I was wondering what formula I should use to solve the problem.

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- Thread starter williams31
- Start date

- #1

- 38

- 0

A) 4390 N

B) 10,260 N

C) 5870 N

D) 7300 N

E) 8780 N

I was wondering what formula I should use to solve the problem.

- #2

- 63

- 0

- #3

- 38

- 0

Im not sure if I am following you.

- #4

nrqed

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the average force during a collision is the change of momentum divided by the time interval during which the force acts. Here, by change of momentum, I mean the final momentum (after the collision) minu sthe initial momentum (before the collision). You have to be careful, this is a vector difference!williams31 said:

A) 4390 N

B) 10,260 N

C) 5870 N

D) 7300 N

E) 8780 N

I was wondering what formula I should use to solve the problem.

- #5

- 38

- 0

Im lost...but thanks for your guys help anyway.

- #6

nrqed

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First step: find the momentum of the ball *just* before it hits the surface (you may essentially treat its height as being zero). You know it takes 4 seconds to fall and it started from rest so you may find the velocity it has once it reaches the surface. The magnitude of the momentum will be the mass times the speed. (here, I am treating the time that the collision last negligible compared to the time of fall)williams31 said:Im lost...but thanks for your guys help anyway.

Second step: If the collision is elastic, what is the momentum just after the collision? If you take the momentum vector just after minus the momentum vector just before the collision, you get a difference which is not zero. What is its magnitude?

Third step: take this last result and divide by the time interval of the collision.

- #7

Andrew Mason

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What is the height that the ball is dropped from? (You can work this out from the time of the round trip).williams31 said:Im lost...but thanks for your guys help anyway.

What is its velocity just before it strikes the plate?

What is it after?

What is the change in velocity?

What is the change in momentum?

What is the relationship between (average) Force, time, and change in momentum?

Answer those questions and you will have your answer.

AM

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