Question

A rod of length 5 m is moving at a speed of 0.6 c. To an observer sitting perpendicular to the direction of motion, the length appears to be _______________

(a) 5 m
(b) 4 m
(c) 3 m
(d) 2 m

Answer 1

When an object is moving at a high speed, its length appears to decrease from the perspective of an observer. The rod is moving at a speed of 0.6 c, so its length appears to be contracted.

Step-by-step explanation:

When an object is moving at a high speed, it undergoes a phenomenon called length contraction. According to the theory of special relativity, as the speed of the object approaches the speed of light, the length of the object appears to decrease from the perspective of an observer.

In this case, the rod is moving at a speed of 0.6 c, which means it is moving at 0.6 times the speed of light. Therefore, the length of the rod appears to be contracted, or shortened.

Since the length of the rod is 5 m, and it is moving at a significant fraction of the speed of light, the length appears to be less than 5 m. Therefore, the correct answer would be (c) 3 m.