# Homework Help: Impulse of a ball

1. Jun 13, 2010

### mickellowery

1. The problem statement, all variables and given/known data
A 0.150 kg ball is dropped 1.25m from rest. It rebounds to a height of 0.960m. What is the impulse given to the ball by the floor?

2. Relevant equations
I=$$\Delta$$p and p=mv were the equations I was trying to use. I was pretty sure I should use F=ma since the only other thing that I know is acceleration due to gravity. I don't know anything about time so I ruled out $$\int$$$$\sum$$Fdt.

3. The attempt at a solution

2. Jun 13, 2010

### Staff: Mentor

Good. So how can you figure out the velocity just before and just after it hits the floor?

Hint: When the ball is in the air, it's just a projectile.

3. Jun 13, 2010

### kuruman

Using I = Δp is the correct approach. Can you find what v just before and just after the collision? If so, then you can find Δv and from this Δp.

4. Jun 13, 2010

### mickellowery

So can I use the kinematics equations? Since I don't know anything about time can I use vf2= vi2+2a (xf-xi) to find the velocity?

5. Jun 13, 2010

### Staff: Mentor

Sounds good to me.

6. Jun 13, 2010

### mickellowery

thanks kindly to all!!