you cannonbal into the water from a 15m diving board.what velocity do you hit the water and what work is done by the water if you stop 1.9m below the surface? Mass=85kg.

What did you try to do to solve the problem?

For the first part, use the formula :v^2 = u^2 + 2as

v is the final velocity
u is the initial velocity (at the diving board)
a is the acceleration due to gravity
s is the displacement.

The directions need to be considered. If you take up to be positive, make sure everything that is going up is positive and the rest is negative for the formula to work. The opposite is also true.

Now, your speed decreases from the final velocity v you got above to zero along a distance of 1.9 m. Use the formula I just gave you to find the acceleration (or deceleration) that the water applies on you.

Then, use F=ma to find the force exerted by water on you.

Finally, use Work\ Done = Force \times Distance to find the work done by water.