Question

A flywheel in the form of a uniformly thick disk of radius 1.23 m has a mass of 50.1 kg and spins counterclockwise at 267 rpm . Calculate the constant torque required to stop it in 3.75 min .

Answer 1

The moment of inertia of the flywheel can be given as MR²/2

I = 50.1kg x (1.23m)²/2 = 37.9 kg m²

Now the flywheel is spinning at 267rpm which means that every minute it turns about 267 x 2 angle Thus the angular velocity of the wheel can be given as w = 267 x 2/60 = 27.96 s^-1

Now if the wheel has to stop in 3.75 min the angular acceleration needed will be

w = t

=> 27.96 = x 3.75 x 60

=> = 0.124267 s^-2

Now torque T = I = 4.71 Nm