A 70.0-kg grindstone is a solid disk 0.530m in diameter. Youpress an ax down on the rim with a normal force of 160N(Figure 1) . Thecoefficient of kinetic friction between the blade and the stone is0.60, and there is a constant friction torque of 6.50N?m betweenthe axle of the stone and its bearings.
A.How much force must be applied tangentially at the end of acrank handle 0.500 m long to bring the stone from rest to 120rev/min in 8.00s ?
B.After the grindstone attains an angular speed of 120 rev/min,what tangential force at the end of the handle is needed tomaintain 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?
