The statement shows a case of rotational motion, in which the disc <em>decelerates</em> at <em>constant</em> rate.
i) The angular acceleration of the disc (
), in revolutions per square second, is found by the following kinematic formula:
(1)
Where:
- Initial angular speed, in revolutions per second.
- Final angular speed, in revolutions per second.
- Time, in seconds.
If we know that
,
y
, then the angular acceleration of the disc is:


The angular acceleration of the disc is
radians per square second.
ii) The number of rotations that the disk makes before it stops (
), in revolutions, is determined by the following formula:
(2)
If we know that
,
y
, then the number of rotations done by the disc is:

The disc makes 3.125 revolutions before it stops.
We kindly invite to check this question on rotational motion: brainly.com/question/23933120