Our scuba diver, still at a depth of $40\mathrm{.}0m,$ finds a $28\mathrm{.}8cm$ diameter cannon ball. They pick it up and then release it from a stationary point $($its initial velocity is zero$).$ At that time, what is the instantaneous acceleration of the cannon ball in the downward direction, in $\frac{m}{s^2}?($Enter a positive number as your answer!$)$ Take the specific gravity of the cannon ball to be $11\mathrm{.}8$ and the density of water to be $1000k\frac{g}{m}3.$