a 70-kg person rides in a 30-kg cart moving at 12 m/s at the top of a hill that is in the shape of an arc of a circle with a radius of 40 m. (a) what is the apparent weight of the person as the cart passes over the top of the hill? (b) determine the maximum speed that the cart may travel at the top of the hill without losing contact with the surface. does your answer depend on the mass of the cart or the mass of the person? explain.