. 10 . (49 + 36) = 425 J of kinetic energy and the yellow puck hed 0 J. Therefore it is impossible for the green puck to have * . 10 . (81 + 4) = 425 J of kinetic energy after the collision if the yellow puck has any. Lastly, answer choice D can be disqualified because it suggests that the total kinetic energy after the collision to be less than the total kinetic energy before the collision. In the cage of answer B, momentum has been conserved. The green puck gained 10 Ns in the i direction and 20 Ns in the j direction, which is equal to the momentum the yellow puck lost. The kinetic energy of the green puck after the collision is 2 - 10 . (64 + 16) = 400 J. The kinetic energy of the yellow puck after the collision is , . 10 . (1 + 4) = 25 J. The sum is 425 J. so kinetic energy has also been conserved