posted by beavis on .
A driver has 50kg mass, and drives from a high board. On entering the water the driver travels vertically downward and comes to rest in a vertical distance of 5 m. The average resistance force is acting on the driver during the motion to rest in the water is three times her weight. how high is the board?
(please show the formulas you've used..thank you)
Let F = 3*M*g be the average resistance force in the water. Let d = 5m be the vertical distance the water is penetrated. Let H = the board height above water.
Underwater net force * d = Kinetic energy entering water = Initial potential energy
(F - M*g)*d = M*g*H
2*M*g*d = M*g*H
H = 2 d = 10 m