The Velocity Addition Formula
Velocity Addition Formula Updated: March 28, 2026 On the Electrodynamics of Moving Bodies Einstein-EDoMB-1905-Section §5 https://www.fourmilab.ch/etexts/einstein/specrel/www/ Einstein: Relativity, The Special and the General Theory, 1920, Chapter VI page 19, Chapter XIII page 45 https://www.google.com/books/edition/Relativity/n8QKAAAAIAAJ?hl=en&gbpv=1 Both sources show the velocity-addition-formula as it is today. Shown: V = ( v + w ) / ( 1 + vw/c² ) #### Lorentz Transforms Lorentz Transforms – subtraction, shown in EdoMB-1905 Section §3 and used in Section §4 ( length contraction and time dilation. ) Shown in Halliday & Resnick as equations 37-2I: x′ = gamma • ( x – vt ) t′ = gamma • ( t – vx / c² ) Lorentz Transforms – addition, shown in H&R as equations 37-22. Shown neither in Section §5 ( v-a-f ) nor in Chapter XIII ( v-a-f ): x = gamma • ( x′ + vt′ ) t = gamma • ( t′ + vx′ / c² ) #### Transition from subtraction to addition Halliday & Resnick, 10th Edition, Ch...