A man stands on a frictionless rotating platform which is rotating with an angular
speed of 1.0 rev/s; his arms are outstretched and he holds a weight in each hand. With his hands in
this position the total rotational inertia of the man, the weights, and the platform is 6.0 kgm2
. If by
drawing in the weights the man decreases the rotational inertia to 2.0 kgm2
, (a) what is the resulting
angular speed of the platform? (b) By how much is the kinetic energy increased?
A man stands on a platform that is rotating (without friction) with an angular speed of 1.21 rev/s; his arms are outstretched and he holds a brick in each hand The rotational inertia of the system consisting of the man, bricks, and platform about the central axis is 4.32 kg·m2. If by moving the bricks the man decreases the rotational inertia of the system to 1.13 kg·m2, (a) what is the resulting angular speed of the platform and (b) what is the ratio of the new kinetic energy of the system to the original kinetic energy?
1 answer
1 answer