A diver of mass 45 kg jumps from a diving board and reaches a maximum height of 10 m above the surface of the water in a swimming pool. Assume Earth’s gravitational field strength is 10 N kg–1 , that air resistance is negligible, and that the diver is treated as a point particle. What is the diver’s kinetic energy as she hits the water, and at what speed does she hit the water?

Answer:

19) E

At the maximum height of 10m, the diver would have maximum gravitational potential energy (GPE).
GPE = mgh = 45 x 10 x 10 = 4500 J
The moment before she makes contact with water, all of her GPE would be converted into kinetic energy (KE). Therefore, her KE as she hits the water would = 4500 J
To calculate the speed at which she hits the water, we use the kinetic energy formula.
KE =
1
2
・mv
4500 = 0.5 x 45 x v2
200 = v2
v = √√200 = √2 x 10 x 10 =
E is the answer.
10√2 m2
2