Answer
The period of the pendulum is $2.5~s$
Work Step by Step
We can find the angular frequency $\omega$:
$v_m = A~\omega$
$\omega = \frac{v_m}{A}$
$\omega = \frac{0.50~m/s}{0.20~m}$
$\omega = 2.50~rad/s$
We can find the period:
$T = \frac{2\pi}{\omega}$
$T = \frac{2\pi}{2.50~rad/s}$
$T = 2.5~s$
The period of the pendulum is $2.5~s$.
