What holds a moon in its orbit? OA. its own internal magnetism
OB. the heat generated by the planet it orbits
OC. the gravitational pull of the star it orbits
OD. the gravitational pull of the planet it orbits

Complete these sentences. if a roller coaster train has a potential energy of 1,500 j and a kinetic energy of 500 j as it starts to travel downhill, its total energy isj. once the roller coaster train gets closer to the bottom of the hill, its kinetic energy increases to 1,100 j, and its potential energy decreases to j. when the train reaches the bottom of the track and is traveling along the ground, its kinetic energy isj.