- #1

- 73

- 0

## Homework Statement

A ball of mass 3

*m*collides head-on with a initially stationary ball of mass

*m*. No kinetic energy is transformed into heat, or sound. In what direction is the mass-3

*m*ball moving after the collision, and how fast is it going compared to its original velocity?

## Homework Equations

p=mv

## The Attempt at a Solution

I initially set it up as p1i +p2i = p1f +p2f

p2i being zero it was discarded from the equation

so p1i = p1f + p2f

3mv = 3mv1f + mv2f since m is a unknown constant I can remove it from the equation

3v = 3v1f + v2f

unfortunately, this is where I am stuck :(

or should I have calculated this via Kinetic energy?