A flywheel of mass 190 kg with a radius of gyration of 0.1 m is accelerated uniformly from rest to 1800 rpm. The driving torque is a constant 90 N·m and friction can be ignored. How long t does this take?
A flywheel of mass 260 kg has a radius of gyration of 0.15 m about its axis. It spins at 1000 rpm. Find its kinetic energy Ek in kJ.
A flywheel with a moment of inertia of 7 kg·m² spins at 900 rpm. A brake applies a constant friction torque of 140 N·m. How many revolutions N does the flywheel make before it stops?
A uniform slender rod of mass 6 kg and length 0.7 m is pinned at one end and released from rest in a horizontal position. Ignore friction and use g = 9.81 m/s². Find the angular velocity ω of the rod as it swings through the vertical position.
A person stands on a frictionless turntable and holds a 2 kg dumbbell in each hand, 0.9 m from the axis. The person and turntable alone have a moment of inertia of 2 kg·m² about the axis. They turn at 25 rpm, then pull the dumbbells in to 0.35 m from the axis. Treat the dumbbells as point masses. Find the new speed n2 in rpm.
A uniform solid disc (mass 20 kg, radius 0.5 m) spins freely at 550 rpm about a vertical frictionless shaft. A thin ring of mass 19 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.
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