physics
posted by Anonymous .
A wheel of 40cm radius rotates on a stationary axle. It isuniformly speeded up from rest to a speed of 900 rpm in a time of20s. Find (a) the constant angular acceleration of the wheel and(b) the tangential acceleration of a point of a point on itsrim.

(a) convert 900 rpm to radians per second and divide by 20s. That is usually called alpha, in radians/s^2
(b) tangential acceleration = R*(alpha)
This is basic stuff. Show your work if additional assistance is needed