(a)
The angular acceleration can be calculated by using the following equation:
where:
is the final angular speed
is the initial angular speed
is the angular acceleration
is the number of revolutions made by the disk while accelerating
Solving the equation for , we find
(b) 3.23 s
The time needed to complete the 50.0 revolutions can be found by using the equation:
where
is the final angular speed
is the initial angular speed
is the angular acceleration
t is the time
Solving for t, we find
(c) 3.94 s
Assuming the disk always kept the same acceleration, then the time required to reach the 11.0 rev/s angular speed can be found again by using
where
is the final angular speed
is the initial angular speed
is the angular acceleration
t is the time
Solving for t, we find
(d) 21.7 revolutions
The number of revolutions made by the disk to reach the 11.0 rev/s angular speed can be found by using
where:
is the final angular speed
is the initial angular speed
is the angular acceleration
is the number of revolutions made by the disk while accelerating
Solving the equation for , we find