A rigid body of mass is mounted on a fixed axle passing through a point

PHYSICS · Multi-part · A Level · Physics · Engineering physics · Engineering physics

Problem

A rigid body of mass

M

is mounted on a fixed axle passing through a point

O

. Its moment of inertia about this axle is measured experimentally to be

I

. (i) Define the radius of gyration of the body about the given axis. (ii) Starting from the definition, obtain an expression for the radius of gyration

k

in terms of

I

and

M

. (iii) Two bodies each of mass

5\,\text{kg}

have radii of gyration

20\,\text{cm}

and

40\,\text{cm}

respectively about the same axis. Explain which body has a larger fraction of its mass closer to the axis and why.

Related theory

Moment of Inertia
Rotational dynamics

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