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1. How do we know that objects mass increase as they approach the speed of light
2. How did whoever figured this out do so
2. How did whoever figured this out do so
1. How do we know that objects mass increase as they approach the speed of light
2. How did whoever figured this out do so
1. How do we know that objects mass increase as they approach the speed of light
I hear from somewhere that the Universe is expanding at speeds greater than the speed of light. Does that count?traveling at various speeds up to almost the speed of light
I hear from somewhere that the Universe is expanding at speeds greater than the speed of light. Does that count?
http://en.wikipedia.org/wiki/Faster-than-light#Universal_expansion
You will still find "relativistic mass" as a concept in modern materials like Feynman lectures http://www.feynmanlectures.caltech.edu/I_toc.html
http://www.einstein-online.info/elementary/specialRT/emc is a quite readable presentation of experiments in which relativistic mass has to be taken into account.
Because energy and relativistic mass are different names for the same quantity, "mass" in a relativistic context is nowadays most often taken to mean the rest mass or invariant mass.
You will still find "relativistic mass" as a concept in modern materials like Feynman lectures
haha. I guess I need more practise with English."Count" in what sense?
How does the energy increase?
How does the energy increase?
So basically the acceleration gives it the energy increase?
[itex]E=\frac{m_0c^2}{\sqrt{1-(v/c)^2}}[/itex]. Calculus shows that when v increases, E increases.
Mathematically, that is the most convenient way of interpreting that equation but as I pointed out, that is not what happens physically. The energy has to increase for the speed to increase, otherwise you have cause and effect backwards.
the way you've stated it, there would have to be a spontaneous increase in speed and that would CAUSE the energy increase, which is not how it works.
Energy increases according to [itex]\dot E = \vec F \cdot \vec v[/itex]. Thus when starting from rest the energy can't increase if the speed doesn't increase first.
Energy increases according to [itex]\dot E = \vec F \cdot \vec v[/itex]. Thus when starting from rest the energy can't increase if the speed doesn't increase first.
So you are saying that the speed increases magically, without the application of any force.
There's no "first" here - they increase together smoothly from zero in the idealized case.
Let's leave that equation and come to this ##E_k=\frac{1}{2}mv^2## (The kinetic energy equation)No, I'm saying energy isn't increasing without speed.