Required information NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. A roller coaster starts from rest at A, rolls down the track to B, describes a circular loop of 4O-ft diameter, and moves up and down past Point E. Take h = 64 ft and assume that there is no energy loss due to friction. Dr= 20 ft E C

Part a) Determine the force exerted by his seat on a 170-lb rider at B and D

Part b) Determine the minimum value of the radius of curvature at E if the roller coaster is not to leave the track at that point.