A 50.0-kg grindstone is a solid disk 0.52m in diameter. You press an ax down on the rim with a normal force of 160N. The coefficient of kinetic friction between the blade and the stone is 0.60, and there is a constant friction torque of 60.5N.m between the axle of the stone and its bearings. (a) how much force must be applied tangentially at the end of a crank handle 0.50m long to bring the stone from rest to 120rev/min in 9s? (b) after the grindstone attains an angular speed of 120rev/min what tangential force at the end of the handle is needed to maintain a constant angular speed of 120 rev/min (c) how much time does it take the grindstone to come from 120rev/min to rest if it is acted on by the axle friction alone

A 50.0-kg grindstone is a solid disk 0.52m in diameter. You press an ax down on the rim with a normal force of 160N. The coefficient of kinetic friction between the blade and the stone is 0.60, and there is a constant friction torque of 60.5N.m between the axle of the stone and its bearings. (a) how much force must be applied tangentially at the end of a crank handle 0.50m long to bring the stone from rest to 120rev/min in 9s? (b) after the grindstone attains an angular speed of 120rev/min what tangential force at the end of the handle is needed to maintain a constant angular speed of 120 rev/min (c) how much time does it take the grindstone to come from 120rev/min to rest if it is acted on by the axle friction alone