Question

A roller coaster ride in a park includes a vertical drop of 60 m. Assume that the roller coaster has a speed of nearly zero when it reaches the top of the hill. Neglecting friction, find the speed of the riders at the bottom of the hill. 

Answer 1

We can find the speed of the riders at the bottom of the hill from the law of conservation of energy:

$$KE=PE,$$ $$\dfrac{1}{2}mv^2=mgh,$$ $$v=\sqrt{2gh}=\sqrt{2\times9.8\ \dfrac{m}{s^2}\times60\ m}=34\ \dfrac{m}{s}.$$