|
7.2 THE NATURE OF LIGHT
SPECIAL REALTIVITY P72 002 A person on the surface of the Earth observes two spacecraft at
once instance of time to be the same distance above them. At this instance,
spacecraft A is stationary while the other spacecraft B is approaching the
observer at a speed v when
they both send a light signal and fire rockets (same muzzle velocity) to the
observer. Comment on the times at which the light signals and rockets reach
the observer on Earth. Explain your answer View solution below only after you have completed answering the question. The solution is not in a form that you would answer in an examination. The answers are often in more detail to help improve your appreciation and understanding of the physics. |
|
Solution The speed of light is a constant and does not depend upon the relative motions of the Earth and the spacecrafts. The light signals travel the same distance, hence the light from A and B will arrive at the observer at the same time (simultaneously). This is not the case for the rockets. The rocket from B will arrive first because it travels at a larger velocity than the rocket fired from A, since, the speed of rocket B is equal to the muzzle velocity (launch velocity of the rocket w.r.t. the spacecraft) plus the speed of the spacecraft as it approaches the observer on Earth. |