Special Relativity by Griffiths 2 | The Geometry of Relativity

A lecture based on David J. Griffiths, Introduction to Electrodynamics, 4th edition (Cambridge University Press, 2017), Section 12.1.2. Topics: the relativity of simultaneity; time dilation and the factor gamma, with muon decay as experimental evidence (Example 12.1); the twin paradox; Lorentz contraction and the measurement of length; the barn and ladder paradox; why perpendicular dimensions do not contract; and the invariant interval. Problems 12.5, 12.7, 12.8, 12.9 and 12.10 are worked step by step. Each problem is stated first, with a pause sign, so you can attempt it before the solution. Chapters 0:00 Introduction 0:50 The relativity of simultaneity 2:42 A Galilean counterexample 4:03 Seeing versus observing 5:09 Problem 12.5: synchronized clocks along a line 6:03 Time dilation: the light clock 7:59 The factor gamma 9:28 Muon decay (Example 12.1) 10:48 Problem 12.7: the speed of a muon 12:35 Reciprocity of time dilation 14:45 The twin paradox 16:37 Problem 12.8: a light signal from a rocket 18:17 Lorentz contraction 20:43 Measuring a length 22:24 Problem 12.9: Lorentz contraction of a moving car 23:31 The barn and ladder paradox 25:58 Perpendicular dimensions 27:20 Problem 12.10: the angle of a moving mast 28:26 The invariant interval 29:23 Summary Previous: section 12.1.1, Einstein's postulates. Animated with Manim Community Edition.