Answer
$v_m=4.4\frac{m}{s}$
Work Step by Step
We know that
$v_m=\omega{X_m}$
where $'v_m'$ represents maximum speed, similarly '$X_m'$ is the amplitude and $'\omega'$ is the angular frequency
given that $X_m=35cm=\frac{35}{100}m=0.35m$
Now put the values in the first equation
$v_m=(12.6)(0.35)=4.41 \frac{m}{s}$
or $v_m=4.4\frac{m}{s}$
