Posted by maria on .
A roller coaster starts from rest 85m above the ground . Assume there is no energy lost when it reaches the top of the secound hill , which is 55m high. How fast is the tolerant coaster moving?

physics . 
drwls,
The potential energy loss equals the kinetic energy gain. The mass will cancel out and you will be left with
g*(85  55) = V^2/2
Solve for V