Answer
(a) $0.018\frac{rad}{s}$
(b) $250m$
Work Step by Step
(a) The angular frequency is given as
$\omega=\frac{2\pi}{T}$
We plug in the known values to obtain:
$\omega=\frac{2\pi}{5.7min}(\frac{1min}{60s})$
$\omega=0.018\frac{rad}{s}$
(b) The amplitude of the vibration can be calculated as follows:
$A=\frac{v_{max}}{\omega}$
We plug in the known values to obtain:
$A=\frac{4.5}{0.018}$
$A=250m$
