PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
Two identical hockey pucks, A and B, each of mass m, slide without friction on a horizontal ice rink.
• Puck A moves due east with constant speed v0.
• Puck B moves due north with the same speed v0.
The two pucks collide and stick together, forming a single composite puck.
Assume the brief collision is the only significant interaction and the ice offers negligible external horizontal force.
(a) Sketch momentum vectors for pucks A and B immediately before the collision and draw the single momentum vector for the composite puck immediately after the collision. Label all vectors clearly.
(b) Using your sketch and appropriate reasoning, determine the direction of motion of the composite puck with respect to the east–west axis. Express your answer as an angle measured north of east.
(c) Explain qualitatively (no calculations required) whether the speed of the composite puck after the collision is less than, equal to, or greater than v0. Support your answer with clear reasoning based on momentum conservation.