1. The problem statement, all variables and given/known data A 350kg roller coaster starts from rest at point A and slides down the frictionless loop-the-loop shown in the accompanying figure. http://session.masteringphysics.com/problemAsset/1027487/5/1027487.jpg 1. How fast is this roller coaster moving at point B? 2. How hard does it press against the track at point B? 2. Relevant equations 1. it has potential energy at A = mgh =350*9.8*25= 85750 joules at B it has PE = 350*9.8*12=41160 joules the difference has been changed to kinetic energy = 1/2 mv^2 1/2 mv^2 = 1/2 (350)v^2 =85750 - 41160 =16 m/s this is good. 3. The attempt at a solution 2. F = mv^2/R = 350*16^2/6 = 14933.3 It says this isnt the answer.