The Velocity Addition Formula
Velocity Addition Formula Updated: November 5, 2024 On the Electrodynamics of Moving Bodies Einstein-EDoMB-1905 https://www.fourmilab.ch/etexts/einstein/specrel/www/ Section §5 presents the velocity-addition-formula used today. Shown: V = ( v + w ) / ( 1 + vw/c² ) #### A new blog We set aside an earlier, very long version of the blog, eight typescript pages, an incredible degringolade. That version contains the velocity-addition-formula shown above and a velocity-subtraction-equation: V = ( v – w ) / ( 1 – vw/c² ) We now do a much abbreviated blog which does only subtraction and addition of distances, not subtraction and addition of speeds. #### Newtonian Subtraction: 60 = 80 – 20 ← x′ = x – vt Addition: 80 = 20 + 60 ← x = vt + x′ These numbers are taken over from the earlier train model. In both a subtraction and addition, a train of length 60 miles is on the track. Again, in common, the train moves 20 miles in 1 hour, its caboose going to track mile [ x = 20 ] and train fro