1. Chapt1 Relativity Dr. Maha Torjman

11.  - impossibility of measuring the speed of the ether with respect to the Earth and the faliure of the Galilean velocity transformation equation in the case of light.  - Einstein proposed a theory that boldly removed these difficulties and at the same time completely altered our notion of space and time.  He based his special theory of relativity on two postulates: Dr. Maha Torjman

14.  We restrict the discussion to the concepts of simultaneity, time intervals, and lengths  This three of which are quite different in relativistic mehanics from Newtonian mechanics.  1-3-1- Simultaneity and the Relativity of Time: Einstein devised the following thught experiment to illustrate this Point : Dr. Maha Torjman

20.  O concludes that, because of the motion of the vehicle, if the light is to hit the mirror, it must leave the Laser at an angle with respect to the vertical direction.  Comparing Figure (a) with Figure(b), we see that the Light must travel faster in (b) than in (a).  Second postulate of the special theory of relativity : O and O / must both measure C for the speed of Light.  The light travels farter in the frame of O so ( The time interval ∆t measured by O is longer than the time interval ∆tp measured by O/.  This effect is known as time dilation.  Using the right triangle shown in Figure ( 1.5.c), the Pythagorean theorem gives : Dr. Maha Torjman

22.  ∆t p is called the proper time Dr. Maha Torjman

28. The Proper Length Dr. Maha Torjman