Answer
(a) $0.25$, $\frac{4\pi}{3}$, $\frac{3}{4\pi}$.
(b) see graph.
Work Step by Step
(a) Given $y=-0.25cos(1.5t-\frac{\pi}{3}$, we can find the amplitude $0.25$, period as $\frac{2\pi}{1.5}=\frac{4\pi}{3}$, and frequency of the motion as $\frac{3}{4\pi}$.
(b) see graph.