Answer
a) $f=733Hz$
b) $a_{max}=13.4m/s^2$
Work Step by Step
a) We have $v_{max}=A\omega=A(2\pi f)$, so $$f=\frac{v_{max}}{2\pi A}$$
$v_{max}=2.9\times10^{-3}m/s$ and $A=6.3\times10^{-7}m$, so $$f=733Hz$$
b) We have $$a_{max}=A\omega^2=v_{max}\omega=v_{max}(2\pi f)$$ $$a_{max}=13.4m/s^2$$
