# Physcis help 2

1. Jun 14, 2012

### Ereny

1. The problem statement, all variables and given/known data

A marble with a mass of 2.0 grams moves to the left with a velocity of 2.0m/s when is collides with a 3.0 gram marble moving in the opposite direction with a velocity of 2.0 m/s. if the first marble has a velocity of 1.5m/s to the right after the collision determine the velocity of the second marble after the collision.

2. Relevant equations

(before) m1v1 + m2v2 = m1v1 + m2v2 (after)

3. The attempt at a solution

i need help setting it up and i will be all good..

2. Jun 14, 2012

### rock.freak667

Split the problem up into what is happening before and after the collision

From reading the problem you can see that the first line gives what is happening before collision. If we take left direction as negative, the the first marble has the mass = 2 g and velocity = - 2 m/s.

So what is it's momentum? Do the same for the 3 g marble.

Now you add them up and you will have the total momentum (i.e. the momentum before collision - left side of your relevant equations).

The second line tells you what is happening after collision, do the same here and equate the two. (call the velocity of the second marble v)