Calculating Angular Velocity & Revolutions for a Merry-Go-Round

[sauri]

A merry-go-round is accelerated from rest by a child at a steady acceleration of 0.2 rad.s-2.

1)How long does it take for the merry go round to reach an angular velocity of 1.4 rad.s-1?
2)How many revolutions does the merry go round (and the child) make in this time?

I believe I worked out the first one, where a=w/t. so t=w/a (t=1.4/0.2). Am I correct?.

However I can't understand the second part..is there an equation to find the number of revs?

 

[phucnv87]

The first question, I think you're right.
For the second one, find the angle \theta=\frac{1}{2}at^2
The revolutions are N=\frac{\theta}{2\pi}[/color]

 

[sauri]

is it ok to use w=\theta/t to find the angle?

 

[Hootenanny]

is it ok to use w=\theta/t to find the angle?

<br /> <br /> No because this will only give you an average angular frequencey. As there is acceleration you need to use the equations phuncv87 posted.