A flywheel of mass 20 kg with a radius of gyration of 0.55 m is accelerated uniformly from 1000 rpm to 1700 rpm. This takes 25 s. Ignoring friction, find the constant torque T needed.
A pendulum is made of a uniform slender rod (5 kg, 1.5 m long) pivoted at its top end O, with a thin solid disc of mass 4 kg and radius 0.1 m fixed to its lower end. The disc swings in its own plane and its centre is 1.6 m below O. Find the mass moment of inertia IO of the pendulum about O.
A flywheel with a moment of inertia of 7 kg·m² spins at 1700 rpm. A brake applies a constant friction torque of 140 N·m. How long t does it take to stop?
A uniform slender rod of mass 9 kg and length 2.9 m is pinned at one end and held horizontal. It is released from rest. Use g = 9.81 m/s². Find the vertical force R that the pin exerts on the rod just after release.
A solid sphere rolls without slipping down a slope inclined at 30° to the horizontal. Use g = 9.81 m/s². It starts from rest. How long t does it take to roll 6 m down the slope?
A hollow sphere of mass 18 kg rolls without slipping at 6 m/s. Find its rotational kinetic energy Erot.
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