A meter stick having a rest mass of 1 kg moves past you. Your measurements show it to have a mass of 2 kg and a length of 1 m. How is the stick oriented, as observed by you?
A) perpendicular to its direction of motion
B) parallel to its direction of motion
C) It is impossible to say anything about the orientation without further information.
D) Nonsense-- if the stick's mass has increased to 2 kg, then it must be longer than 1 m.

Question

Quizplus · Accepted Answer

The length contraction only occurs in the direction of motion. Since the length is measured as 1 m (the same as its rest length), the stick must be oriented perpendicular to its direction of motion.

A Meter Stick Having a Rest Mass of 1 Kg