What is the torque of a cd after accelerating to 500 rev/min in 3.0 revolutions?

[ryty]

Homework Statement

When play is pressed, a cd accelerates uniformly from rest to 500 rev/min in 3.0 revolutions. If the Cd has a radius of 5.5 cm, and a mass of 20 g, what is the torque?

Homework Equations

not sure, this is my problem. i think its torque=angular acceleration*inertia. but i don't know how to turn "500 rpm in 3.0 revolutions" into angular acceleeration

The Attempt at a Solution

nothing, i don't how to make the equations work

 

[flatmaster]

You have your analogy from linear kinematics equations to rotational motion equations.

a = delta v / delta t

So the same is true for rotational acceleration, and change in rotational velocity

 

[ryty]

but how does torque fit into this equation?

 

[borvis]

You can use: $$\omega^{2}=2\alpha s$$ , where $$s=2\pi r * 3$$ (3 times the circumference)

and 500 $$rev/min=4770 rad/sec$$