Answer:
11.07s
Step-by-step explanation:
Angular acceleration constant
w = w* + αt
The initial angular speed is
w* = 89 rev/min ( 2πrad/1rev)×(1min/60secs)
w* = 89rev/min(2×3.14rad/1rev)(1min/60secs)
= 558.93/60
= 9.315rad/s
The time to reach final speed = wf
Where wf = 0
α = -0.841rad/s ( the negative sign here is as a result of it deceleration)
t = wf - w*/α
Where
t is the time taken the s seconds
wf is the final angular speed
w* is the initial angular speed
t = 0 - 9.315/-0.841
t = -9.315/-0.841
t = 11.07s