4 ms·
For the people who (like myself) are confused by the missing c^2 in the blog, (u + v)/(1+(uv/(c^2)) is the original. Much easier to understand that the "simpli
by xxxvvv 8y ago
For the people who (like myself) are confused by the missing c^2 in the blog, (u + v)/(1+(uv/(c^2)) is the original.
Much easier to understand that the "simplified" version, which is usually the case.
- zinclozenge 8y agoIn relativity, c=1 is a common convention. It doesn't really add much to the equation because it's just a conversion factor.
- archgoon 8y agoOmitting conversion factors is a bit like omitting type information. If you already know what everything is, it doesn't add information, and can make the code look simpler. If you don't, not omitting them can help make sense of things when you're learning and lack context.
- wzcard 8y agoTo get back a meaningful result for the car example, c=1 does not really help. It is much easier to plug in u and v directly into the simpler equation that contains c^2. Otherwise (the indirect method), to get fractions, first you do a substitution a=u/c, b=v/c, arrive at: c * (a * b) / (1 + a * b) Then you convert the car speeds to fractions, only to multiply back by c=299792458. Curiously enough, this sort of thing rarely occurs in the original publications, so they are usually easier to read than obfuscated textbooks or blog examples.