Posted by Themba on Tuesday, July 22, 2014 at 11:06am.
A cliff diver,mass 75kg,free falls off a cliff that is 50m above the water surface.He hits the water surface and stops 5m under the surface.calculate:
4.1 The net force while free falling.
4.2 The divers' velocity when he reaches the water surface.
4.3 calculate the time it takes the water to stop the diver.

physical sciences  bobpursley, Tuesday, July 22, 2014 at 11:12am
net force when falling= zero
velocity at water hit: 1/2 m v^2=mg*50
v= sqrt(100g)
time to stop in water is rather complicated, unless you assume the acceleration is constant at hitting until stopping (a ridiculous assumption), and that force is constant (another ridiculous assumption).
With those assumptions
Vf^2=Vi^2+2ad where a= force/mass
solve for force