The 800-lb roller-coaster car starts from rest on the track having the shape of a cylindrical helix.

Question:

The 800-lb roller-coaster car starts from rest on the track having the shape of a cylindrical helix. If the helix descends 8ft for every one revolution, determine the speed of the car in t = 4s. Also, how far has the car descended in this time? Neglect friction and the size of the car.