Circular motion and radial acceleration

[ptejav]

Homework Statement

A particle moves with a constant angular acceleration Alpha in a circular path. The time at which the magnitude of tangential and radial accelerations are equal is
a) 1/Alpha b) Sq.root Alpha c) 1/Sq.root Alpha d) Alpha

Homework Equations

The Attempt at a Solution

I worked more than two days on this problem but could not get answer.

 

[w3390]

This does not even require any work. Just use dimensional analysis. First figure out what the units of angular acceleration are. Since you know what the units of time are, figure out which choice yields units of seconds.

 

[Delphi51]

So you have ω = α*t. Have you a formula for finding the tangential velocity from that? If you know calculus, you can then get the tangential acceleration easily with a derivative.

Any formula for radial acceleration?

We aren't supposed to give away solutions here - you have to give evidence of trying the problem!