1. A 100 g puck is sliding in the x-direction at 5 m/s with negligible friction. The first puck collides with a second 100 g puck that was not moving before the collision. Right after the collision the first puck has completely stopped. Using your best physics intuition, what is the velocity of the second puck? Be sure to give the speed and direction the second puck is moving and briefly explain your reasoning.