At the highest point of motion the ball comes to rest momentarily,but it is being pulled down due to the effect of gravity,so its net acceleration is downwards. So,just after that point,it starts falling downwards.
I'm not 100% sure but I think the answer is 60.4, because you multiply 3.20 by 10, to get 32 - 9 = 23, then subtract 23 from 83.4. Hope this helps you, and good luck!!!
