Answer:
[tex]v(t)=\dfrac{3\pi}{5}\cos{(3\pi t)}[/tex]
Step-by-step explanation:
The velocity is the derivative of position.
[tex]s(t)=3+ \dfrac{1}{5} \sin{(3\pi t)}\\\\v(t)=s'(t)=\dfrac{1}{5}(3\pi)\cos{(3\pi t)}\\\\\boxed{v(t)=\dfrac{3\pi}{5}\cos{(3\pi t)}}[/tex]