Calculating moment of inertia&torque?A Farris Wheel has its mass mF=200 kg of its rim and a radius of 8.0 m.

A Farris Wheel has its mass mF=200 kg of its rim and a radius of 8.0 m. Assume that it all mass is on the rim and spokes’ mass is negligible.
(a) Calculate its moment of inertia.
(b) How much torque will be needed to increase its angular speed  from zero to 5 rad/s in 20 seconds?
(c ) Calculate its angular momentum L when its angular speed is 5.0 rad/s.
(d) How much work will be done by the torque used in part (a)?

a) I = m*R² = 200*8² = 12800 kg∙m²

b) Q = I*α = 12800*[5/20] = 3200 N∙m

c) L = w*I = 5*12800 = 64000 kg∙m²/s

d) W = KE = ½I*w² = ½*12800*5² = 1.6 MJ