A clock is moving across an observer's line of sight with its face turned toward the observer. Which of these statements about this clock, as seen by the observer, is correct?
A) The clock will run slow compared with a clock in the observer's hand.
B) The clock will appear longer than it would if it were at rest.
C) The clock will appear thicker, front to back, than it would if it were at rest.
D) The clock will appear less massive than it would if it were at rest.

Question

Quizplus · Accepted Answer

According to the theory of relativity, a moving clock appears to run slower compared to a stationary clock from the perspective of an observer. This phenomenon is known as time dilation.

A Clock Is Moving Across an Observer's Line of Sight