How to find angular acceleration

[itsmarasilly]

Homework Statement

A propeller slows from 450 rev/min to 200 rev/min in 3.50 s. What is its angular acceleration?

Homework Equations

ac = v^2/r
and v = rw

The Attempt at a Solution

I know this is probably a simple problem, but what do the variables in the relevant equations refer to?

 

[asleight]

Homework Statement

A propeller slows from 450 rev/min to 200 rev/min in 3.50 s. What is its angular acceleration?

Homework Equations

ac = v^2/r
and v = rw

The Attempt at a Solution

I know this is probably a simple problem, but what do the variables in the relevant equations refer to?

Here are some more relevant equations:

\frac{1 rev}{min}=\frac{1 rev}{60 s}=\frac{\pi rad}{30 s}, and
\vec{\alpha}_{ave}=\frac{\Delta\vec{\omega}}{\Delta t}.