A green puck with mass 10 kg strikes a stationary yellow puck with mass 10 kg. The green puck was moving at a velocity of 7i – 6j m/s, and its center was at (1, 2) when it hit the yellow puck. Which of the following could be the velocities of the pucks after the collision? (Assume the collision is elastic.)

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.