A spaceship is moving toward the Earth at a speed v along th

A spaceship is moving toward the Earth at a speed v along the x axis. A meter stick in the spaceship, which is originally parallel to the x axis, is now rotated to be perpendicular to the x axis. After correcting for time differences in transmission of light from different parts of the meter stick, what is the length L for the meter stick calculated by the astronaut in the spaceship?

A) L increases.

B) L decreases.    

C) L doesn\'t change.

D) The answer depends on the exact value of v.

Solution

The length of the meterstick does not change.

Reason:1) Meter stick is at rest relative to the astronaut in the spaceship.

             2)According to length contraction, the length of body is contracted along the directionof motion. So the meterstick is perpendicular to the direction of motion.