- #1

## Homework Statement

A ball of mass m rolls down a 3.0 m ramp inclined at 30° above the horizontal, rolls along a flat, friction less surface, and collides elastically with another ball of mass 2m, initially at rest. The second mass then moves along the surface and collides with a horizontally mounted spring with spring constant k= 200 N/m, compressing it by 0.15 m. What is the value of m?

## Homework Equations

E

_{k 1}+ E

_{g 1}+ E

_{e 1}= E

_{k 2}+ E

_{g 1}+ E

_{e 2}

For the incline:

F

_{N}+ F

_{g parallel}+ F

_{g perpendicular}+ F

_{f}= m

_{1}a

## The Attempt at a Solution

I've been working backwards so I started with this:

1/2 m

_{2}v

_{2}'

^{2}= 1/2 kx

^{2}

I ended up with v

_{2}' = √45/2m and I now have no idea how to continue

Any help will be appreciated.