A0.100–kilogram white ball moving with a velocity of 5 meters/second along the positive x–axis hits a stationary blue ball of the same mass. energy is not necessarily conserved, but momentum is. after the collision, the white ball moves off at an angle of 20° with respect to the positive x–axis and at a velocity 3.5 meters/second. the blue ball moves at an angle of –35° and a velocity of 2.1 meters/second. what is the final y–momentum of the system?