Question

The diagram given below shows a ski jump. A skier weighing 60 kgf stands at A at the top of the ski jump. He moves from A and takes off for his jump at B.

(a) Calculate the change in the gravitational potential energy of the skier between A and B.

(b) If 75% of the energy in part (a) becomes kinetic energy at B, calculate the speed at which the skier arrives at B.(Take g=10 m$s^{-2}$.

Answer 1

(a)
Given : m = 60 kgf

height of A= 75m from ground

height of B= 15m from ground

Distance moved from A to B= 75 - 15 = 60m

Potential energy = mgh

P.E = 60$\times$60$\times$10 = 36000 J

where g=

(b)

75 % 0f 36000 = $\times$ 36000 = 27000J

Using formula (1)

27000 =

v = 30m/s