Answer
$s(1) = -2$
The object is moving downward at time $t=1$.
Work Step by Step
$s(t) = -4~cos~\frac{5\pi}{3} t$
When $t = 1$:
$s(1) = -4~cos~[\frac{5\pi}{3} (1)] = -4(0.5) = -2$
On the graph, we can see that the slope of the graph is negative at time $t = 1$. Therefore, the object is moving downward at time $t=1$.