Calculate the point along a line joining the centre of earth and moon where there is no gravitational force. (Given: mass of Earth = 6×10^24 kg, mass of Moon = 7.4×10^22 kg, distance between centre of earth and moon = 3.8×10^8 m).

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.