Natural Science Forum / Physics / Research / January 2008

mark_horn@sbcglobal.net schrieb:

If you are interested in a relative accuracy of 10^-4 or below, yes.
Otherwise probably not.

Relativistic corrections tend to be of the order of (v/c)^2.

Arnold Neumaier

When a body's relative velocity adds mass-energy approaching its rest
mass, that is relativistic beyond argument.  What relative velocity
deviates from Newtonian expectations by 1%?

1/sqrt[1-(v^2)/c^2)] = 1.01
sqrt[1-(v^2)/c^2)] = 0.990099
1-(v^2)/c^2) = 0.9803
(v^2)/c^2) = 0.01970
v/c = 0.14

At 14% of lightspeed you will deviate from Newton by 1%.  At 10% of
lightspeed you should start thinking "Special Relativity."

In article
<a801130c-8659-40f1-9a21-719184f53dec@e4g2000hsg.googlegroups.com>,
mark_horn@sbcglobal.net writes:

I don't think there is any standard definition.  Even if there were, it
wouldn't be of much use, because it depends on context.  If relativistic
calculations (or, if the relativistic effects are small, relativistic
"corrections"---perhaps not proper full-scale calculations, but rather
adding terms from a series expansion or whatever) are important for what
you are interested in---meaning that if you neglect them, you care about
the difference between the non-relativistic and relativistic
calculation---then the velocity is relativistic.  If not, it is not.  
This will depend both on the accuracy you are interested in and also on
what order in v/c the effect in question shows up.