Question

A 55 kg skier is at the top of a slope. The vertical distance between start and finish is 10m. (a) What is her Potential Energy? (b) How fast is she moving at the bottom of the hill?

Answer 1

Explanation:

Given that,

Mass of a skier, m = 55 kg

The vertical distance between start and finish is 10 m.

(a) The potential energy of a skier is given by :

$E=mgh\\\\E=55\times 9.8\times 10\\\\=5390\ J$

(b) When she reaches the bottom of the hill, the potential energy is converted to kinetic energy. So,

$5390=\dfrac{1}{2}mv^2\\\\v=\sqrt{\dfrac{2\times 5390}{55}} \\\\v=14\ m/s$

Hence, her potential energy is 5390 J and at the bottom of the hill she is moving with a speed of 14 m/s.