A hoop of 2.00-m circumference is rolling down an inclined plane of length 10.0 m in a time of 10.0 s. It started out from rest.
(a) What is its angular velocity when it arrives at the bottom?
(b) If the mass of the hoop, concentrated at the rim, is 1.50 kg, what is the angular momentum of the hoop when it reaches the bottom of the incline?
(c) What force(s) supplied the net torque to change the hoop's angular momentum? Explain. [Use a rotation axis through the hoop's center.]
(d) What is the magnitude of this force?