A roller coaster starts from rest at the top of a 90 m hill. How fast will it be going at the bottom of the hill, if there is no friction?

Answer 1

In this equation we will be using conservation of energy, notably potential and kinetic.

potential energy = mgh

kinetic energy = (1/2)mv²

As energy is conserved:

mgh = 1/2 mv²

gh = 1/2 v²

v² = 2gh

v = √2gh

v = √2(9.8)(90)

v = 42 m/s

Hope this helps!