College Physics with MasteringPhysics 7th Edition by Jerry Wilson,Anthony Buffa,Bo Lou

تمرين 25

A flat cylindrical grinding wheel is spinning at 2000 rpm (clockwise when viewed head-on) when its power is suddenly turned off. Normally, if left alone, it takes 45.0 s to coast to rest. Assume the grinder has a moment of inertia of 2.43 kg · m 2. (a) Determine its angular acceleration during this process. (b) Determine the tangential acceleration of a point on the grinding wheel if the wheel is 7.5 cm in diameter. (c) The slowing down is caused by a frictional torque on the axle of the wheel. The axle is 1.00 cm in diameter. Determine the frictional force on the axle. (d) How much work was done by friction on the system