# Coefficient of Restitution

1. Sep 26, 2012

### bionut

Hi all, I know this may see basic but how would I go about calcualting Impact velovity?

The only information I have is:
Height dropped, height bounced and from here I can calculate the CofR...

But how would I go about finding impact velocity

2. Sep 26, 2012

### CWatters

Conservation of energy.

3. Sep 26, 2012

### bionut

YEs, I thought of that... but dont know the mass of the ball?

4. Sep 26, 2012

### SammyS

Staff Emeritus
Use m for the mass of the ball.

Both KE & PE are proportional to the mass, m.

Last edited: Sep 26, 2012
5. Sep 27, 2012

### hms.tech

I don't get the question, i think it is wrong just because there is no need for the Coefficient of Restitution to find the impact (final ) velocity .

The Equations for constant acceleration , once applied would be used to find the Impact velocity AND the rebound velocity

6. Sep 28, 2012

### SammyS

Staff Emeritus
Some mechanical energy is lost in the bounce. Thus there is a coefficient of restitution.