Answer:
The magnitude of the drills angular acceleration is .
The drill makes 50 revolutions before it stops.
Explanation:
The revolutions that the drill makes in 1 second is
And the angular velocity is
(<em>one revolution is </em><em> radians)</em>
Now, the drill comes to a halt in 2.5 s, which means the magnitude of it's angular acceleration is
In other words, the magnitude of the angular acceleration is
Now, we find the angular displacement of the drill which is given by the equation
putting in , , and , we get:
which is
<em>(one revolution is </em><em> radians)</em>
50 revolutions.
In other words ,the drill makes 50 revolutions before it stops.