Question

An air hockey puck traveling in the positive x direction hits another puck sitting at rest at the origin, in an elastic collision. After the collision, the first puck has has a speed less than before, and a path at an angle below the positive x axis (in the fourth quadrant). The stone originally at rest is now moving in what direction? O straight in the positive x direction O at an angle above the positive x axis (first quadrant) at an angle below the positive x axis (fourth quadrant) O straight in the positive y direction

Answer 1

In elastic collision the total momentum of the system before collision is equal to momentum after collision. So the X and Y components of momentum should be conserved before and after collision.

To after collision the puck sitting at rest before collision will move at an angle above positive x axis after the collision.

The second option is correct.