You are Here: Home

# Restitution

Announcements Posted on
Uni student? You could win a Samsung Galaxy S7 or £500 of travel vouchers by taking this quick survey 05-05-2016
Talking about ISA/EMPA specifics is against our guidelines - read more here 28-04-2016
1. See attachment for question. I need help with part three, where I thought that sqrt(0.05) was the answer. The answer is 0.5, by the way.
Attached Thumbnails

2. (Original post by bbrain)
See attachment for question. I need help with part three, where I thought that sqrt(0.05) was the answer. The answer is 0.5, by the way.
By restitution, since the ground isn't moving:

"velocity after impact" = -e ("velocity before impact")

Post some working if it's not coming out.
3. The speed of B immediately before impact = 2 ms^-1
The speed of B immediately after impact = sqrt(2^2-2*g*0.05) = sqrt(3)
Then e is not 0.5

4. (Original post by bbrain)
The speed of B immediately after impact = sqrt(2^2-2*g*0.05) = sqrt(3)
That's not correct, but I don't know what you're doing to get there.
5. So what should I do?
6. Knowing it reaches a height of 0.05m, you can either use conservation of energy, or .

Since you're not telling me what you did use, I can't tell why it's incorrect.
7. Got it. Since v=2gh=2*10*0.05 =1, and the speed before impact =2, 1/2=0.5
8. (Original post by bbrain)
Got it. Since v=2gh=2*10*0.05 =1, and the speed before impact =2, 1/2=0.5

Hence and hence .

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: May 23, 2012
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

## Groups associated with this forum:

View associated groups
Study resources
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.