For a rigid body the radius of gyration is defined by

PHYSICS · Subjective · AP · Physics 1: Algebra-based · Torque and Rotational Dynamics · Torque and Rotational Dynamics

Problem

For a rigid body the radius of gyration

k

is defined by

I = Mk^{2}

, where

M

is the mass and

I

the moment of inertia about a given axis. (a) Show, by dimensional arguments, that

k

possesses the dimension of length. (b) A flywheel has mass

4.0\,\text{kg}

and moment of inertia

0.080\,\text{kg}\,\text{m}^{2}

about its axis. Calculate its radius of gyration. (c) Briefly explain the physical significance of the radius of gyration for this flywheel.