# Homework Help: Velocity on a rotating disk

1. Jun 6, 2010

### aks_sky

1. The problem statement, all variables and given/known data
If you are standing on a rotating disk which is rotating at a constant angular velocity and you walk with a speed v along a straight radial line, then what are you velocity and acceleration?

2. Relevant equations

3. The attempt at a solution
I just wanted to check if the linear velocity in this case will be:

v=w*r

and then the acceleration will just be the centripetal acceleration or am i understanding it wrong.

2. Jun 6, 2010

### superiority

The problem says that you're moving along a straight radial line - imagine that the disk has a straight line from the circumference to the centre, and, as the disk rotates, you start at the centre and walk along this line to the edge. If you were standing in one spot on the disk, then you would have $v = r \omega$ and $a = \frac{v^2}{r}$, but in the situation described, there is an additional component. I think it should just be vector addition of velocities (in two dimensions), and acceleration would be found by differentiating the vector of velocity.

3. Jun 6, 2010

### aks_sky

cheers. i get it now