A flywheel of mass 150 kg with a radius of gyration of 0.3 m is accelerated uniformly from 800 rpm to 1800 rpm. The driving torque is a constant 49 N·m and friction can be ignored. How long t does this take?
A flywheel of mass 240 kg has a radius of gyration of 0.6 m about its axis. It spins at 300 rpm. Find its kinetic energy Ek in kJ.
An 8.5 kg block hangs from a light cord wrapped around a pulley, a uniform solid disc of mass 9 kg and radius 0.45 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 flywheel with a moment of inertia of 39.5 kg·m² spins at 300 rpm. A brake applies a constant friction torque of 105 N·m. How many revolutions N does the flywheel make before it stops?
A uniform slender rod of mass 9 kg and length 0.9 m hangs at rest from a frictionless pivot at its top end. A 20 g bullet moving horizontally at 380 m/s hits the rod 0.51 m below the pivot and stays embedded. Find the angular velocity ω of the rod just after the impact.
A person stands on a frictionless turntable and holds a 1 kg dumbbell in each hand, 0.85 m from the axis. The person and turntable alone have a moment of inertia of 3 kg·m² about the axis. They turn at 20 rpm, then pull the dumbbells in to 0.15 m from the axis. Treat the dumbbells as point masses. Find the new speed n2 in rpm.
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