A grindstone in the shape of a solid disk with diameter 0.529 m and a mass of 50.0 kg is rotating at 850 rev/min. You press an ax against the rim with a normal force of 160 N, and the grindstone comes to rest in 7.50 s.
Find the grindstone's angular acceleration in rad/s2.
Find the coefficient of friction between the ax and the grindstone.