An observer on a planet sees a spaceship approaching at 0.5c. A beam of light projected bythe ship would be measured by this observer to travel at:
A)0.25c.
B)0.5c.
C)c.
D)1.5c.
E)2.5c.

Question

Quizplus · Accepted Answer

According to the theory of relativity, the speed of light is constant for all observers, regardless of their relative motion. Therefore, the observer on the planet would still measure the speed of light to be c, even if it is projected by a spaceship traveling at 0.5c. Choices A, B, D, and E violate this principle and are incorrect. According to Einstein's theory of relativity, the speed of light (c) is constant for all observers, regardless of their relative motion. Therefore, the beam of light projected by the spaceship would also be measured as traveling at the speed of light (c) by the observer on the planet.

An Observer on a Planet Sees a Spaceship Approaching at 0.5c