When a 50.0 kg skier (initially at rest) skis down a ramp from a vertical height of 2.0 m, she attains a speed of 4.0 m/s. a) What is the skier's

When a 50.0 kg skier (initially at rest) skis down a ramp from a vertical height of 2.0 m, she attains a speed of 4.0 m/s.

a)      What is the skier's total mechanical energy at the top of the ramp?

b)     What is the skier's total mechanical energy at the bottom of the ramp?

c)      What is the percent efficiency of the ramp?