# Translational velocity help

1. Apr 14, 2009

Translational velocity help!!!

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

A ball is on an incline with µ = 30±. Its initial height is 1.5 m. When
it reached the bottom of the incline, what is the ball’s translational (linear)
velocity? [Use conservation of energy to solve.]

2. Relevant equations

r= s$$\vartheta$$

3. The attempt at a solution
r= (1.5)sin(30)

I am confused with this problem because a radius was not given and I am not sure if I started it right...

2. Apr 14, 2009

### whybother

Re: Translational velocity help!!!

I think you aren't going about the problem the way your teacher intended - Go with the hint, to use conservation of energy.

At the top of the ramp, the ball is not moving, so all the energy is in the form of potential energy. At the bottom of the ramp, all of the energy is now in kinetic energy. Your relevant equations should be the form of potential and kinetic energy knowing that Initial Energy = Final Energy here. They specify linear velocity too, to let you know that basically the rotation of the ball is to be ignored (ie. you don't really need to concern yourself with the radius).