# Homework Help: Disk on a motion

1. Apr 13, 2013

### BBAI BBAI

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

Adisk of radius R centred at the origin is placed on a frictionless x-y plane with origin as the centre of the disk.At t=0, the disk is given initial motion such that the point A(R,0) has velocity v towards
+ve x axis and ω=v/2R. Find the coordinates of Point A at t= 4piR/v
2. Relevant equations

∅=ωt..That's all i think is needed

3. The attempt at a solution
i used but i am getting a wrong answer help!

2. Apr 13, 2013

### Staff: Mentor

Can you express the motion of A as functtion of the velocity of the center and ω?
Based on that, can you calculate this velocity and ω?

3. Apr 13, 2013

### BBAI BBAI

That's the problem..The velocity of A at t=0 is given..How can i relate to the centre of mass velocity..

4. Apr 13, 2013

### Staff: Mentor

I proposed to start with the other direction (use w,ω for the center and calculate the motion of A as function of those variables) for a good reason - it is easier.
Did you try to calculate it?