Is this done properly, please help

Ion1776

The blades of a fan rotate clockwise at −225 rad/s at medium speed, and −355 rad/s at high speed. If it takes 3.05 seconds to get from medium to high speed, what is the average angular acceleration of the fan blades during this time?

Is the answer

-(355-225)/3.05

= 42.6 rad/s^2

Please work it out and tell me if I did this correctly

tiny-tim

Hi Ion1776!

(try using the X² tag just above the Reply box )
Yup, that's fine! …

(apart from the sign)

the usual constant acceleration equations apply to angular distance speed and acceleration just as they do to linear distance speed and acceleration …

in this case, you can (and did) use v - u = at.