Question

A 66.0kg diver is 4.90m above water, falling at speed of 6.70m/s. Calculate her kinetic energy as she hits the water. Neglect air friction

Answer 1

kinetic energy = 1/2 m v^2

m= mass = 66 kg

h= height = 4.9 m

v = speed = 6.70 m/s

KE = 1/2 (66) (6.7)^2 = 1,481.37 J

PE = potential energy = m g h

g = gravity = 9.8 m/s^2

PE = 66 (9.8) (4.90) = 3,169.32 J

When he hits the water potential energy is converted into kinetic energy:

E = KE + PE = 1,481.37 + 3,169.32 = 4,650.69 J

Answer: 4,650.69 J