shows a ski -jump. A skier of mass 60 kg stands at A at the top of the ski-jump. He moves from A to B 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 the kinetic energy at B, calculate the speed at which the skier arrives at B.

Answer

A, B, C

Explanation

Here, mass of the skir, m =60kg
change in height h =75m -15m =60m
(a) Change in gravitational potential energy of the skier, i.e., `E_p = mgh =(60kg)(10m//s^2)(60m ) =36xx10^3 J`
(b) `E_k = (75%) E_p = (3)/(4)xx36xx10^3J =27xx10^3J`
As `E_k =(1)/(2)mupsilon^2, upsilon = sqrt((2E_k)/(m)) = sqrt((2xx27xx10^3J)/(60kg)) = 30m//s`