Measuring the moment-of-inertia of a rigid body using a swing-pendulum

Abstract

Abstract A novel way to construct a compound pendulum is to suspend a distributed mass from a single pivot using light inextensible strings. Here we describe how such a compound ‘swing-pendulum’ can be used to infer the moment-of-inertia of a rigid body. Our approach is particularly suitable for contexts in which it is impractical to suspend the body from one of its internal points, and is illustrated using data sourced from student-led experiments on steel and aluminium rods.