As a meterstick moves past you, your measurements show its momentum to be twice its classical momentum and its length to be 1 m. In what direction is the stick pointing?
Solution 33E The meter stick’s length did not change in this case. We know the law of length contraction in relativity and it happens only when the object moves parallel to the observer. So the length did not change tells that the stick must have travelled in some direction which is perpendicular to your motion. The momentum got doubled, and it can happen even if the stick moves in a perpendicular direction to your motion. CONCLUSION: So the stick points in a perpendicular direction to your motion.