The roller coaster and its passenger have a total mass m. Determine the smallest velocit...

The roller coaster and its passenger have a total mass m. Determine the smallest velocity it must have when it enters the loop at A so that it can complete the loop and not leave the track. Also, determine the normal force the tracks exert on the car when it comes around to the bottom at C. The radius of curvature of the tracks at B is and at C it is Neglect the size of the car. Points A and C are at the same elevation.