The mass of a roller coaster car, including the riders, is 516 kg. The path of a portion of the ride is shown in the diagram below. The radii of curvature at the three points A, B, and C are 174 m, 11.0 m, and 7.00 m, respectively. The car, which travels from right to left, has a speed of 12.8 m/s and 22.5 m/s at A and B, respectively C (a) What is the force exerted by the track at these two locations? (Enter the magnitudes of the forces.) At A At B (b) At what minimum speed will the car lose contact with the track at C m/s