# Homework Help: Impulse question

1. May 4, 2006

### williams31

A 56g steel ball is released from rest and falls vertically onto a steel plate. The ball strikes the plate and is in contact with it for .5 ms. The ball rebounds elastically, and returns to its original height. The time interval for a round trip is 8.00 s. In this situation, the average force exerted on the ball during contact with the plate is closest to:
A) 4390 N
B) 10,260
C) 5870 N
D) 7300 N
E) 8780N

im confused by this problem..it seems like something is missing

2. May 4, 2006

### asdf60

nothing is really missing, you just have to make a few assumptions. you have the time the ball takes to fall, and hence assuming g, you know the velocity as it hits the steel plate. You also know the velocity as the ball leaves the steel plate upwards, so you know the change in momentum from before the ball hits to after the ball hits. can you figure out the impulse then?

3. May 5, 2006

### Andrew Mason

This is a https://www.physicsforums.com/showthread.php?t=119457". Why are you not following up on the previous posts? As we have said, you have to find the height of the ball first.

AM

Last edited by a moderator: Apr 22, 2017