An amusement-park ride consists of a large circular platform of radius fixed in position
PHYSICS · Multi-part · CBSE · Physics · System of Particles and Rotational Motion · System of Particles and Rotational Motion
Problem
An amusement-park ride consists of a large circular platform of radius 2.5m fixed in position. The platform is set into rotation about its central vertical axis while its center of mass remains at rest. Riders stand on the platform, and the total mass of the platform plus riders is 1.2×103kg. During operation the angular speed of the platform is kept constant at ω=2.0rads−1.
Assume the riders are distributed so that the rotational inertia of the system about the central axis is 3.0×103kgm2.
(a) Describe, without using numerical calculations, how the rotational kinetic energy of the ride depends on both the mass distribution of the riders and the angular speed of the platform.
(b) Two separate groups of riders of equal total mass choose different positions on the platform. Group A crowds near the center while Group B stands near the rim. For the same operating angular speed ω, which group results in a larger rotational kinetic energy for the system? Explain your reasoning qualitatively in terms of rotational inertia.