Question

section 7.3: the special theory of relativity
7 - 10 you are in a spaceship moving in a straight line at constant speed. you cannot see out of the ship. assuming perfectly uniform motion, which of the following is true?
a. you could determine that you are moving by measuring changes in the motion of a ball thrown parallel to the direction you are traveling.
b. you could determine that you are moving by measuring changes in the motion of a ball thrown perpendicular to the direction you are traveling.
c. you could determine that you are moving by measuring the change in length of the ship you are in.
d. there is no experiment you can do to determine that you are moving.
e. (b) and (c) are both correct.

Explanation:

In special relativity, for an observer in a spaceship moving with a perfectly uniform motion, there is no way to determine the motion of the spaceship itself through internal experiments. Measuring the length of the ship won't indicate motion as length - contraction is relative to an external observer. Measuring changes in the motion of a ball thrown parallel or perpendicular to the direction of travel also won't give a clue about the spaceship's motion because all inertial frames of reference are equivalent. There is no experiment that can be done inside the uniformly - moving spaceship to determine that it is moving.

Answer:

D. There is no experiment you can do to determine that you are moving.