A .4 kg ball is attached to a spring with spring constant 12 N/m. If the ball is pulled down .2m from the equilibriu, and released, what is its maximum speed while it oscilates?

(1/2)kX^2 = (1/2) M Vmax^2

Vmx = X*sqrt(k/m)

X is the maximum amount the spring is stretched (or compressed)