Steps important A 60 kg skier starts from rest at height H

A 60 kg skier starts from rest at height H = 20 m above the end of a ski- jump ramp and leaves the ramp at an angle theta. Neglect the effects of air resistance and assume the ramp is frictionless. After leaving the ramp, the skier reaches a maximum height h = 5m above the end of the ramp. What is the kinetic energy of the skier when he leaves the ramp? (12,000 J) What is the kinetic energy of the skier when he reaches maximum height h after leaving the ramp? (9,000 J)

Solution

(A) Applying energy conservation for top and end of ramp:

PE + KE at top = PE + KE at end of ramp

(m g H) + 0 = 0 + KE

KE = 60 x 9.8 x 20 = 11760 J

(use g = 10 m/s^2 instead of 9.8 m/s^2 then KE = 12000 J)

(B) now applying energy conservation again for h,

m g H + 0 = m g h + KE

KE = m g (H -h) = 60 x 10 x (20 - 5) = 9000 J