A roller-coaster car may be represented by a block of mass 50.0 kg. The car is released fromrest at a height h = 45.0 m above the ground and slides along africtionless track. The car encounters a loop of radius R = 15.0 mat ground level, as shown. As you will learn in the course of this problem, the initial height 45.0 m is great enough so that the carnever loses contact with the track. Find an expression forthe kinetic energy K of the car at the top of the loop. Find the minimum initial height at which the car can be released that still allows the car to stay in contact with the track at the top of the loop.