Answer to Question #287982 in Classical Mechanics for Dom

Question

the loaded roller coaster has a mass of 2500 kg. the starting point of the run is 22m above point A; the run from B to C is 120m long; the run from C to D is 100m. at D, brakes are applied, bringing the coaster to a halt 15m further along a E. if the friction from B to D is 0, find

(a) the potential energy of the roller coaster at the starting point

(b) KE of the roller coaster at C

(c) the speed of the roller coaster at D; the average braking force applied between D and E

Answer 1

(a) $PE=mgh=539000\text{ J}.$

(b) $KE=PE_A=539000\text{ J}$ assuming B to C is a horizontal part of the track.

(c) Since the friction is 0, the average braking force is zero.