Question

A roller coaster cart with a mass of 1283 kg starts on a hill that is 189 m off the ground. The hill descends all the way to the ground, before going back up hill. How fast is the roller coaster going when it reaches the ground?

Answer 1

From the conservation of energy:

$$0.5mv^2=mgh$$

$$v=\sqrt{2gh}=\sqrt{2(9.81)(189)}=60.9\frac{m}{s}$$