PHYSICS · Subjective · CBSE · Physics · System of Particles and Rotational Motion · System of Particles and Rotational Motion
Problem
Four homogeneous bodies, each having mass M and outer radius R, are prepared as follows:
A : a thin circular ring (hoop)
B : a solid disc
C : a thin spherical shell (hollow sphere)
D : a solid sphere
Each body can rotate freely about its symmetry axis passing through its centre (for the spheres, about any diameter).
Answer the following:
(i) Arrange the four bodies in ascending order of their moments of inertia about the stated axes.
(ii) Give a qualitative explanation for your ranking in part (i) with reference to mass distribution and the idea of radius of gyration.
(iii) If all four bodies are set into rotation with the same angular speed ω, rank them again in ascending order of rotational kinetic energy. State whether this order is the same as, or different from, the order obtained in part (i) and explain why.