Arotating wheel has a constant angular acceleration. it has an angular velocity of 5.0 rad/s at time t = 0 s, and 3.0 s later has an angular velocity of 9.0 rad/s. what is the angular displacement of the wheel during the 3.0-s interval?

Explanation:

We have equation of motion v = u + at

     Initial velocity, u = 5 rad/s

     Final velocity, v = 9 rad/s    

     Time, t = 3 s

     Substituting

                      v = u + at  

                      9 = 5 + a x 3

                      a = 1.33 rad/s²

     Angular acceleration is 1.33 rad/s²

Now we have equation of motion v² = u² + 2as

     Initial velocity, u = 5 rad/s

     Final velocity, v = 9 rad/s    

     Angular acceleration = 1.33 rad/s²

Substituting  

v² = u² + 2as

9² = 5² + 2 x 1.33 x s

s = 21 radians

Angular displacement during 3 seconds is 21 rad

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.

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