A boy climbs to the roof of his house and drops a 0.40 kg rubber ball from the 7.5-meter peak of the house.

Question

How much energy was lost in the process?

So I got 48 J is this correct?

The bounce takes place over a 170 ms time interval. What is the impulse given to the ball during this time?

74 is this right?

Answer 1

Well. I do not know how much was lost in that first bounce. The answer is all of it after all bouncing has ended.
All of it is m g h =.4 * 9.81 * 7.5=
29.43 Joules

Now I will have to assume that the ball bounced not at all or perfectly. I guess I will assume that it bounced perfectly.
How fast was it going?
(1/2) m v^2 = 29.43 Joules
v = 12.1 m/s down speed
If the bounce is perfect, 12.1 up as well
change in momentum = impulse =
.4 (12.1)(2) = 9.7

The next part of the question is probably what is the average force
F = change in momentum/change in time = impulse/time = 9.7/(.170)

Answer 2

I got 57. 06 N, is that correct?

Answer 3

How do I find the average acceleration of the ball?

Answer 4

9.7/.170 = 57.06 Newtons, yes

F = m a

57.06 = .4 a

a = 143 m/s^2