# Angular acceleration of wheel

## Homework Statement

A 70cm diameter wheels accelerates uniformly from 160 rpm to 280 rpm in 4.00s.
Determine:
a) it's angular acceleration, and
b) the radial and tangential components of the linear acceleration of a point on the edge of the wheel 2.00s after it has started accelerating

a=?
w2= 280rpm
w1= 160rpm
t = 4.0s
d= .7m

a = w2-w1 / t

## The Attempt at a Solution

I used that equation for part a, with a= 280rpm - 160rpm /4.0s
and got a= 30 , but I don't feel that is right. Is there a better equation I could have used?

$$\alpha = \frac{{\Delta}\omega}{{\Delta}t}$$