# Homework Help: Force and Impulse

1. Oct 9, 2008

### bkhofmann

1. The problem statement, all variables and given/known data
The Figure shows an approximate representation of the contact force versus time during the collision of a 66-g tennis ball with a wall. The initial velocity of the ball is 4.375E+1 m/s perpendicular to the wall. What is the speed of the tennis ball after the collision?
(see attached)

2. Relevant equations

3. The attempt at a solution
Not sure how to start, I know the impulse is the area under the curve, thats all. Thanks

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2. Oct 9, 2008

### nasu

And the impulse is also equal to the change in momentum.

3. Oct 9, 2008

### bkhofmann

Ok, having a real brain fart. What do I need to do with the impulse to get the new velocity?

4. Oct 9, 2008

### nasu

impulse=(final momentum)-(initial momentum)
momentum=m*v

5. Oct 9, 2008

### bkhofmann

So just divide the Impulse by the mass?

6. Oct 9, 2008

### nasu

If you just divide, you'll get the difference between the two speeds. Is the problem asking for just this?