An astronaut in a rocket moving with a speed v = 0.6c relative to Earth performs a collision experiment with two small steel balls and concludes the both momentum and energy are conserved.What would an Earth observer conclude?
A) only momentum is conserved
B) only energy is conserved
C) neither energy or momentum is conserved
D) both energy and momentum are conserved

Question

Quizplus · Accepted Answer

According to the principle of relativity, the laws of physics should be the same for all inertial observers, regardless of their relative motion. Therefore, an Earth observer should also conclude that both energy and momentum are conserved in the collision experiment. The conservation of momentum is a fundamental law of physics, and the fact that both momentum and energy are conserved in this experiment is consistent with the theory of special relativity.

An Astronaut in a Rocket Moving with a Speed V