A roller coaster car starts from rest and rolls down a frictionless track, reaching speed v_f at the bottom.
a. If you want the car to go two times as fast at the bottom, by what factor must you increase the height of the track?
b. Does the answer to part (a) depend on whether the track is straight or not? Explain.
The increase in height of the roller coaster is calculated to double its speed at ground.