Our scuba diver, still at a depth of 40.0m, finds a 9.6 cm 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 m/s2 ? (Enter a positive number as your answer!) Take the specific gravity of the cannon ball to be 7.9 and the density of water to be 1000kg/m3