Work-Kinetic Energy Theorem

1. Jan 9, 2016

master_333

1. The problem statement, all variables and given/known data
A high diver(m = 62kg) walks off a platform 15 meters above the water below (assume velocity inital = 0). The diver reaches a depth of 2.2 metres in the pool before coming to a stop.
1. What is the diver's change in kinetic energy (Answer: -9114J)
2. What is the average force of the water pushing up on her? (Answer: 4750 N ... the acceleration corresponds to a about 8 g's)

I don't get the correct answer to the first question and I don' know how to attempt the second question. Please help and please show me the steps.
2. Relevant equations
Work Energy Theorem

3. The attempt at a solution
1. Change in GPE = Change in KE
mgh = change in KE
(62kg)(9.8)(17.2m(
change in KE = 10450.72, which is the wrong answer.

2. Jan 9, 2016

Staff: Mentor

I presume they want the change in KE once she hits the water. So what is her KE when she hits the water?

3. Jan 9, 2016

master_333

The KE when she hits the water is 9114J

4. Jan 9, 2016

Staff: Mentor

There you go. So you can answer part 1 now, correct?

5. Jan 9, 2016

master_333

How do I sart part 2

6. Jan 9, 2016

master_333

Sorry, How do I start part 2

7. Jan 9, 2016

Staff: Mentor

By applying the work energy theorem.

Remember, you are trying to find the average force that the water exerts. What other force acts?