Awindmill is turning at 12.5 rad/s in a clockwise direction. the wind suddenly shifts, producing an angular acceleration of 0.75 rad/s2 in a counterclockwise direction. after 12.0 s, how many revolutions has the windmill blades turned?

Windmill will complete 0.27 revolutions.

Explanation:

We have equation of motion s = ut + 0.5at²

Initial speed, u = 12.5 rad/s

Time, t = 12 seconds.

Angular acceleration, a = -0.75 rad/s²

Substituting

               s = 12.5 x 12 - 0.5 x 0.75 x 12² = 96 rad

1 revolution = 360 rad

So, windmill will complete 0.27 revolutions.

found in the nucleus

has mass of one amu

this would be about 43%