Two pucks slide without friction on an air table. Puck X has mass 0.20kg and moves east at 3.0m/s. Puck Y has mass 0.40kg and moves north at 4.0m/s. They collide and stick together. What is the speed of the combined puck immediately after the collision?
a) 1.7m/s
b) 2.8m/s
c) 3.7m/s
d) 5.0m/s