15. A 0.15 kg glider A is moving to the right on a horizontal, frictionless air track with a speed of 0.80 m/s. It makes a head-on collision with a 0.300kg glider B which is moving to the left with a speed of 2.20 m/s. Assume the collision is elastic, what is the magnitude of the final velocity (in m/s) of glider A?
