A flywheel of mass 40 kg with a radius of gyration of 0.1 m is accelerated uniformly from rest to 700 rpm. The driving torque is a constant 7.3 N·m and friction can be ignored. How long t does this take?
A flywheel of mass 70 kg has a radius of gyration of 0.2 m about its axis. It spins at 600 rpm. Find its kinetic energy Ek in kJ.
A 3 kg block hangs from a light cord wrapped around a pulley, a uniform solid disc of mass 17 kg and radius 0.25 m that turns on a frictionless horizontal axle. The block is released from rest. Use g = 9.81 m/s². Find the tension T in the cord.
A 3.5 kg block hangs from a light cord wrapped around a pulley, a uniform solid disc of mass 10.5 kg and radius 0.1 m that turns on a frictionless horizontal axle. The block is released from rest. Use g = 9.81 m/s². Find the angular acceleration α of the pulley.
A uniform solid disc (mass 18 kg, radius 0.2 m) spins freely at 1000 rpm about a vertical frictionless shaft. A thin ring of mass 3 kg and the same radius is dropped onto it from rest, centred on the shaft, and the two quickly spin together. Find their common speed n2 in rpm.
A thin hoop rolls without slipping down a slope inclined at 20° to the horizontal. Use g = 9.81 m/s². Find the acceleration a of its centre.
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