A flywheel of mass 180 kg with a radius of gyration of 0.3 m is accelerated uniformly from rest to 2000 rpm. The driving torque is a constant 140 N·m and friction can be ignored. How long t does this take?
A flywheel is a uniform solid disc of mass 260 kg and radius 0.55 m. It spins at 400 rpm. Find its kinetic energy Ek in kJ.
A flywheel with a moment of inertia of 20.5 kg·m² spins at 2100 rpm. A brake applies a constant friction torque of 155 N·m. How long t does it take to stop?
A flywheel with a moment of inertia of 23 kg·m² spins at 800 rpm. A brake applies a constant friction torque of 150 N·m. How many revolutions N does the flywheel make before it stops?
A person stands on a frictionless turntable and holds a 2 kg dumbbell in each hand, 0.6 m from the axis. The person and turntable alone have a moment of inertia of 5 kg·m² about the axis. They turn at 35 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.
A uniform solid disc (mass 32 kg, radius 0.25 m) spins freely at 800 rpm about a vertical frictionless shaft. A thin ring of mass 1 kg and the same radius is dropped onto it from rest, centred on the shaft, and the two quickly spin together. How much kinetic energy ΔE is lost in the process?
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