# Thread: gravitational work and potential energy

1. ## gravitational work and potential energy

A professional skier reaches a speed of 56 m/s on a 30° ski slope. Ignoring friction, what was the minimum distance along the slope the skier would have had to travel, starting from rest?

2. $mgh = \frac{1}{2}mv^2$

$h = \frac{v^2}{2g} = \frac{56^2}{19.6} = 160$

now us the fact that for a 30-60-90 triangle, hypotenuse length = twice short side length