Question
1. A fly wheel with a mass of 50 kg is accelerated by an electric motor from rest to an angular velocity of 120rads/s in 14 seconds, if the value of k is 0.3m and there is a frictional torque of 0.07Nm calculate the torque applied, total work and the power from the motor.
Assume the acceleration is constant
Assume the acceleration is constant
Answers
Nonetheless
Angular acceleration of flywheel:
alpha = (120 rad/s - 0 rad/s)/14 s
alpha ~ 8.571 rad/s^2
Moment of inertia of flywheel:
I = mk^2
I = (50kg)(0.3 m)^2
I = 4.5 kg*m^2
Torque applied by motor:
Ta - Tf = I*alpha
Ta - 0.07 N*m = (4.5 kg*m^2)(8.571 rad/s^2)
Ta = 38.64 N*m
Total work done by motor on flywheel:
Work = applied torque*angle
angle = 120 rad/s * 14 s = 168 rad
Work = (38.64 N*m) (168 rad)
Work = ______ J
Power output of motor:
P = work/time
P= ______ J / 14 s
P = _______ W
alpha = (120 rad/s - 0 rad/s)/14 s
alpha ~ 8.571 rad/s^2
Moment of inertia of flywheel:
I = mk^2
I = (50kg)(0.3 m)^2
I = 4.5 kg*m^2
Torque applied by motor:
Ta - Tf = I*alpha
Ta - 0.07 N*m = (4.5 kg*m^2)(8.571 rad/s^2)
Ta = 38.64 N*m
Total work done by motor on flywheel:
Work = applied torque*angle
angle = 120 rad/s * 14 s = 168 rad
Work = (38.64 N*m) (168 rad)
Work = ______ J
Power output of motor:
P = work/time
P= ______ J / 14 s
P = _______ W