Calculating Impulse of a Ball Dropped from Rest

[mickellowery]

Homework Statement

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?

Homework Equations

I=\Deltap 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\sumFdt.

The Attempt at a Solution

 

[Doc Al]

I=\Deltap and p=mv were the equations I was trying to use.

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.

 

[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.

 

[mickellowery]

So can I use the kinematics equations? Since I don't know anything about time can I use v_f²= v_i²+2a (x_f-x_i) to find the velocity?

 

[Doc Al]

So can I use the kinematics equations? Since I don't know anything about time can I use v_f²= v_i²+2a (x_f-x_i) to find the velocity?

Sounds good to me.

 

[mickellowery]

thanks kindly to all!