A grinding wheel is initially at rest question:external torque 60final angular speed is w2 = 1000 rev/min = 104.72 rad/stime :30(60)(30)/ (104.72)= 17.2the frictional force acting on wheel after it reaches final angular velocity = 104.7217.2 x 0 - (104.72/ 160) = 11.25 N.mpage 1571. the rotational analogy forceis torquemass is intertia newton second law is F = ma(constant mass case)2. Moment of inertia : it is the quantity that shows how much resistance a body shows to rotation about a axis for particles,the moment of inertia is I = m * r^2 Now, for the torque torque = Moment of inertia * angular acceleration3.