#### Answer

a. $4\ m$
b. $\frac{5}{2\pi}\ Hz$
c. $\frac{2\pi}{5}\ sec$

#### Work Step by Step

a. Given the motion equation $d=4sin(5t)$, we can get the maximum displacement as the amplitude $A=4\ m$
b. The frequency $f$ can be found in the relation $\omega=2\pi f=5$. Thus $f=\frac{5}{2\pi}\ Hz$
c. The time required for one cycle is the period, which is given by $p=\frac{1}{f}=\frac{2\pi}{5}\ sec$