# Newton's Law of Restitution

1. Jan 9, 2008

### Harmony

1. The problem statement, all variables and given/known data
http://mediocre.wordpress.com/2008/01/09/newtons-law-of-restitution/
Shown in my blog, link provided.

2. Relevant equations
Newton's Law of Restitution, v2 - v1 = e (u1 - u2)

3. The attempt at a solution
I have done the question, actually...but I need confirmation. Can anyone please help me to check whether the no.2 hint is correct or not? (Located at the bottom of the post)

2. Jan 9, 2008

### Shooting Star

Quite correct. The coefficient of restitution is the ratio of the magnitude of the relative velocity of separation to that of the relative velocity of approach in the normal direction.

3. Jan 9, 2008

### Harmony

Yeah, but though I get the answer, I am not sure why only the vertical component of velocity is considered in the 2nd question. Or am I wrong?

4. Jan 10, 2008

### Shooting Star

No, you are right. The vertical component is in the normal direction. For now, you can take it to be a law of nature.