For small displacements, a pendulum is a simple harmonic oscillator. Some have crucial uses, such as in clocks some are for fun, such as a child’s swing and some are just there, such as the sinker on a fishing line. On the bob, which result in a net force of toward the equilibrium position – that is, a restoring force. The linear displacement from equilibrium is, the length of the arc.
Figure 16.14 A simple pendulum has a small-diameter bob and a string that has a very small mass but is strong enough not to stretch appreciably.
