A flywheel of mass 160 kg with a radius of gyration of 0.15 m is accelerated uniformly from 100 rpm to 800 rpm. The driving torque is a constant 88 N·m and friction can be ignored. How long t does this take?
A flywheel of mass 150 kg with a radius of gyration of 0.2 m is accelerated uniformly from 800 rpm to 1900 rpm. This takes 24 s. Ignoring friction, find the constant torque T needed.
A motor brings a flywheel with a moment of inertia of 31 kg·m² from rest up to 2300 rpm in 21 s. Ignoring losses, find the average power Pavg it delivers, in kW.
A uniform slender rod of mass 18 kg and length 2.6 m is pinned at one end and held horizontal. It is released from rest. Use g = 9.81 m/s². Find its angular acceleration α just after release.
A uniform solid disc (mass 17 kg, radius 0.3 m) spins freely at 500 rpm about a vertical frictionless shaft. A thin ring of mass 6 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 uniform slender rod of mass 7.5 kg and length 1 m hangs at rest from a frictionless pivot at its top end. A 25 g bullet moving horizontally at 460 m/s hits the rod 0.4 m below the pivot and stays embedded. Find the angular velocity ω of the rod just after the impact.
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