Angular Accelaration = Angular Velocity^2 ?

[makyol]

Angular Accelaration = Angular Velocity^2 ?

Homework Statement

Can we always says angular accelaration is equal to angular velocity^2? My friend said that i was wrong when think like that to solve question?

Homework Equations

Accelaration = -(angular velocity)^2 X Radius

Acceleration = Radius X Angular Accelaration

The Attempt at a Solution

When i solve those two equations together i get what i hougt. Is there any problem with that? If any please let me know where? Thanks.

 

[Doc Al]

You are mixing up angular acceleration, centripetal acceleration, and tangential acceleration:

Accelaration = -(angular velocity)^2 X Radius

This relates centripetal acceleration to angular velocity:
Centripetal acceleration = ω²R

Acceleration = Radius X Angular Accelaration

This relates tangential acceleration to angular acceleration:
Tangential acceleration = αR