Comments on: Einstein v. Newton

By: Alexis

Alexis — Wed, 12 Aug 2009 02:02:52 +0000

haha yeah..when I saw this I was wondering if this was supposed to be one of those contradictory tattoos or something because anyone finishing a physics degree would know that F=ma falls apart in The Theory of Special Relativity. In Einstein’s theory you have to equate force to the rate of change of momentum, not mass because mass varies. but hey, if thats what you were going for, then great! I love nerd tattoos! if not, then I must say shame on you.

By: Joe

Joe — Sun, 14 Jun 2009 08:23:17 +0000

The best part is both of these equations are wrong in general. They are only correct for certain approximations. The Energy one is only correct if the particle in question has no momentum. The equation for Newtons second law is incorrect in cases of changing mass, for example any rocket or a pickup truck losing furniture on the freeway. The correct versions of both of these would be E^2=\sqrt{p^2c^2 + m^2c^4} and then F=dp/dt=v(dm/dt)+m(dv/dt). A professor at the university where I did my undergraduate degree said the one of the first ways you can tell if someone you are speaking to is a quack is when the inevitably start talking about E=mc^2. The other one is when they tell you they have a theory that you can go faster than the speed of light.

By: Mike

Mike — Sat, 12 Apr 2008 18:22:35 +0000

F=ma would be funny to have across your knuckles.

By: Andrew

Andrew — Tue, 08 Apr 2008 18:22:14 +0000

I think this is my favorite of the bunch. These two formulae, and the men who developed them, rocked the science world like very few others have. They don’t get any more elegant, or fundamental, than these.