Answer:
The total number of revolution is 50 rev.
Explanation:
Given that,
Angular speed = 5.0 rev/s
Time = 8.0 s
We need to calculate the angular acceleration
Using equation of angular motion

Put the value into the formula



We need to calculate the angular displacement
Using equation of angular motion

Put the value into the formula


Now, The washer coming to rest from top spin
We need to calculate the angular acceleration
Using equation of angular motion




We need to calculate the angular displacement
Using formula of displacement

Put the value into the formula


We need to calculate the total number of revolution



Hence, The total number of revolution is 50 rev.