Tangential Acceleration question?

Question

A circular disk of radius 2.0 m rotates, starting from rest with a constant angular acceleration of 20.0 rad/s². What is the tangential acceleration of a point on the edge of the disk at the instant that its angular speed is 1.0 rev/s?

Can anyone show me how this problem is done? I have a feeling I am making it far more complicated than it should be. Thanks to anyone who can help!

Answer 1

Use a fundamental definition of angular acceleration
A=a(tangential)/R hence

a(tangential)=A R
and
a(tangential)= 20.0 x 2=400 m/s^2

We also know that
a(tangential)= V^2/R
V= w R here w=1rev/s or w=2pi rad/s
we have
a(tangential)= (w R)^2/R
a(tangential)=w^2 R
a(tangential)= (2 pi )^2 x 2.0=
a(tangential)=39.5 m/s^2