Question
In a controlled experiment,... a. the outcome is controlled. b. one variable is fixed while all others are changed. c. one variable is changed while all others remainedfixed. d. results are obtained by computer models. Why the observation that the sun sets in the west could becalled a scientific law? Why rotation of Earth could be considered a scientifictheory? In a controlled experiment,... a. the outcome is controlled. b. one variable is fixed while all others are changed. c. one variable is changed while all others remainedfixed. d. results are obtained by computer models. Why the observation that the sun sets in the west could becalled a scientific law? Why rotation of Earth could be considered a scientifictheory?
Explanation / Answer
Given : Specialrelativity theory (SRT) contains two postulates. The firstpostulate is a restatement of Galileo’s relativity principlewhich says that the laws of physics apply equally well for allinertial frames, whether at rest or in uniform rectilinear motion(no acceleration). The second postulate says that the velocity oflight is independent of the speed of its source. This postulate byitself is not strange or unexpected. When a train whistle blows,the speed of sound is independent of the speed of the train, butnot of the velocity of the wind carrying the sound to theobserver. Here, the air molecules are the medium and they play theequivalent role of an aether-wind for electromagnetism. But withrelativity theory, we have no aether. Over time the second postulate has beenreinterpreted to mean that all observers, regardless of their ownvelocity, see light propagating always at the same speed (invacuum). Lengths shorten and time slows so that the computedvelocity (i.e., length divided by time) is alwaysconstant. The paradoxes and problems created by this clever littletrick are endless. Take the case of relativistic interstellartravel. If lengths really contract as viewed by the observer, thenwhen you blast off from Earth, the closer you approach the speed oflight, the closer the receding Earth gets to you. I hope it helps you