Question

A roller coaster has a mass of 275 kg. It sits at the top of a hill with height 85 m. If it drops from this hill, how fast is it going when it reaches the bottom?

Answer 1

`sf(41color(white)(x)"m/s")`

Explanation:

The potential energy of the roller coaster is converted into kinetic energy when it reaches the bottom.

So we can write:

`sf(cancel(m)gh=1/2cancel(m)v^(2))`

`:.` `sf(v=sqrt(2gh))`

`sf(v=sqrt(2xx9.8xx85)=41color(white)(x)"m/s")`

As you can see, the mass given is irrelevant to the question.