Question

A stationary observer views four identical clocks that are traveling at nearly the speed of light. Can observations of the passage of time be used to rank the clocks according to their speeds?

A. Yes. The clock that shows the fastest passage of time is traveling the most slowly, because time slows down nearer to the speed of light.

B. No. The passage of time on each clock depends on the frame of reference of the observer.

C. No. The passage of time on the four clocks should be the same regardless of speed.

D. Yes. The clock that shows the slowest passage of time is traveling the most slowly, because time speeds up nearer to the speed of light.

Answer 1

A. Yes. The clock that shows the fastest passage of time is traveling the most slowly, because time slows down nearer to the speed of light.

Explanation:

It is the theory of relativity which gives a relation between the time recorded by a clock and the speed of the frame of reference in which the clock is.

A clock slows down in a frame of reference that moves at speeds which are close to the speed of light. This is called time dilation according to the theory of relativity.

When the clock is in a moving frame of reference, for example a spaceship, and is observed by a stationary observer, it reads a slower time compared to the clock that is stationary.

Answer 2

The answer would be A. Yes. The clock that shows the fastest passage of time is traveling the most slowly, because time slows down nearer to the speed of light