## College Physics (4th Edition)

The length of the pendulum is $0.994~m$ We can assume that the oscillations move only a small angle from the vertical.
In general: $x(t) = A~cos(\omega~t+\phi)$ In this case: $x(t) = (4.00~cm)~cos~[~(3.14~rad/s)~t~]$ We can see that $\omega = 3.14~rad/s$ We can find the length of the pendulum: $\omega = \sqrt{\frac{g}{L}}$ $L = \frac{g}{\omega^2}$ $L = \frac{9.80~m/s^2}{(3.14~rad/s)^2}$ $L = 0.994~m$ The length of the pendulum is $0.994~m$ We can assume that the oscillations move only a small angle from the vertical.