Question

A skier starts from rest at the top of a 20 degree incline and skis in a straight line to the bottom of the slope, a distance d (measured along the slope) of 400 m. If the coefficient of kinetic friction between the skis and the snow is 0.2, calculate the skier's speed at the bottom of the run.

Answer 1

Answer:

Explanation:

Loss of potential energy = mgh.

h = d sin 20

= 400 sin20 = 136.8 m

Loss of potential energy = m x 9.8 x  136.8

= 1340.64 m

negative work done by friction = μ mg cosθ x d

= .2 x m x 9.8 x cos 20 x 400

= 736.72 m

Net loss of potential energy = 1340.64 m - 736.72 m

= 603.92 m

= gain of kinetic energy = 1/2 m v²

1/2 m v² = 603.92 m

v² = 1207.84

v = 34.75 m /s .