How Does Uniform Angular Acceleration Affect Rotation Angles Over Time?

[JSapit]

Homework Statement

A wheel is subjected to uniform angular acceleration. Initially its angular velocity is zero. During the first 1-s time interval, it rotates through an angle of 90.6degrees.

(a) Through what angle does it rotate during the next 1-s time interval?(in degrees)

(b) Through what angle during the third 1-s time interval?(in degrees)

Homework Equations

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The Attempt at a Solution

I just tried multiplying the 90.6 by 2, and putting in 90.6 itself, because I thought that might be the answer, but I forgot that it was the acceleration, and that the next values would increase in smaller increments, because it is speeding up.

 

[blochwave]

You can use all your equations you've been using for constant acceleration, like d=1/2at^2+Vi*t, but now you use the rotational "versions"

so instead of distance in meters, you have the angle traveled in radians, instead of velocity in meters/second, angular velocity in radians/second, and acceleration is radians/s^2

So in one second it goes from 0 degrees to 90.6 starting from rest(you'll need radians!)this is like knowing distance, time, and initial velocity

 

[JSapit]

Okay, so since I have 5400 rev/min, I divide it by 60 to get 90 rev/sec. Then I multiply it by 2*Pi for the angular velocity in radians, right? Or am I doing something wrong?

 

[blochwave]

That part's right

except the unit is radians/second