Determine the average force that the water exerts on the diver

[pdubb]

A 57.0 kg person jumps from rest off a 11.0 m high tower straight down into the water. Neglect air resistance during the descent. She comes to rest 3.00 m under the surface of the water. Determine the average force that the water exerts on the diver. This force is nonconservative.

i know to use mgh=Fd... i think... but i don't know what distance or height to use or when you are supposed to incorporate the 3.00 m

any help would be apprectiated..

 

[Hakins90]

Yeah you're right, mgh = Fd

The distance that the force from the water acts through is 3m, so distance d = 3m.
Stick that into the equation and you are done :D

 

[pdubb]

when i do mgh=fd...

(57)(9.8)(11)=f(3)
i get 2048.2 N, but its incorrect. what am i doing wrong?

 

[Hakins90]

The height dropped in the fall isn't 11m, it is (11+3)m. Does it work now?

 

[pdubb]

yes, it worked!
thanks so much :)