A firm wants to calculate the amount of frictional torque in their current line of grindstones; therefore they can redesign them to be more energy efficient. To do this, they ask you to test the best-selling model, which is basically a disk shaped grindstone of mass1.0 kilogram and radius 7.80 centimeter which operates at 750 rev/min. When the power is shut off, you time the grindstone and find it takes 36.0 second for it to stop rotating.
(a) Evaluate the angular acceleration of the grindstone?
rad/s2
(b) Find what is the frictional torque exerted on the grindstone?
N•m