Question
A disc of mass M kg and radius R metre is rotating at an angular speed of ω rad/s when the motor is switched off. Neglecting the friction at the axle, the force that must be applied tangentially to the wheel to bring it to rest in time t is
Joshi sir comment
let force is F
then retarding torque about axis = FR
so by τ = Iα calculate α
then use first eq. of motion in rotation
ωf = ωi - αt