A hoop is at rest at the top of a 3.0 m long ramp with an angle of evelation of 24°. If the hoop rolls down the ramp, what is the final velocity of the hoop at the bottom of the ramp
sin 24 = h/3
v = sqrt (2 g h)
Now this is virtually the same as your roller coaster problem. Study conservation of energy and potential energy in gravity field.(mgh) and kinetic energy (.5 m v^2)