Question

An object of length 1 m is moving at speed 0.5c. To an observer at rest relative to the object, the length of the object seems to be ___________

(a) 0.86 m

(b) 0.5 m

(c) 1 m

(d) 0.14 m

I had been asked this question by my school teacher while I was bunking the class.

My doubt stems from Lorentz Transformation Equations in portion Ultrasonics & Relativity of Engineering Physics I

Answer 1

Correct answer is (c) 1 m

Best explanation: The observer at rest relative to the object does not notice any kind of contraction of length of the object. It is so because the scale with which he measures will also get contracted by the same amount.