Why is the Speed of Light Squared in E=mc^2?

In summary: I would like to have a pratical "image" (a pratical experience) of this."In summary, the famous equation e=mc^2 has practical applications in physics and is a hallmark of a good theory. The units of speed squared, m^2/s^2, may not have a direct physical significance, but the crucial point is that (1/2)mv^2 and mc^2 have units of energy. A practical experience to understand this concept could involve reaching the speed of light, but it is not possible to reach this speed due to the "obstacle" of the squared speed of light, c^2."
  • #71
Entropy said:
I did. You don't understand. Binding energy contributes to an atom's mass. Two protons and two neutrons have a smaller mass than a He-4 nucleus. If you don't believe me, look up the masses of [free] two protons and [free] two neutrons and compare it to the mass of a He-4 nucleus. That change in mass is because when these 4 nucleons join to form a single nucleus, known as nuclear fusion, mass from these nucleons is converted directed into energy. The change in mass when plugged into E = mc^2 will yield the exact energy released in the TOTAL reaction. That proves the equation is right. (Note: a more common form of neclear fusion involves H-2 and two protons, which happens in the sun, but it is more complex because it results in the production of positions and this other is reaction is simplier and works for these purposes).

Did you understand that I was talking about the nuclear bombs?
 
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  • #72
Pengwuino said:
You will never find a m^2/s^2 as a real value. You must add hte mass to get kg * m^2/s^2 which is energy. C^2 needs no interpretation because there is no such thing as a square meter per squared second. Its simply a value that needs a mass to go with it before it has any physical meaning

It seems that anything multiplied by mass in Einstein formula will have a physical meaning, probably even potatoes :)
 
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  • #73
russ_watters said:
Not good enough. You say its a general principle, then say you have a specific example: give us your specific example, or admit you have none.

That means that you don't agree with my affirmation? This is a common knowledge between mathematicians; it is similar to fundamental research (or basic research) and applied research.

russ_watters said:
You're claiming that SR is wrong because it hasn't been "completely" proven. Don't you see the contradiction there?

And again, free_mind - doesn't your error in your first post concern you?

edit: So in your first post, you demonstrated that you don't understand the math of units, and in further posts, you demostrated that you don't understand the scientific method (the invalidity of the concept of "completely proven"). With such severe misunderstandings out in the open (you seem to have acknowledged the first, at the very least), don't you think you should take a step back and consider the validity of your opinion?

If you read all my posts you will understand that they are different from the first. I inserted lots of threads, but you fixed you atention at the first one; if you read you will see that the other threads point to different problems.
 
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  • #74
free_mind said:
I knew that m.m/s.s is equivalent to m^2/s^2, this is basic! But even if I had written correctly my doubt about velocity will be underlying my question. But you can see that no one in this forum characterized m^2/s^2. So, this units are something that no one knows what it is! :)

free_mind said:
r^2 is geometrically explainable, but c^2 with it's extraordinary units it's not so easy to explain.


I'm curious.
Do you also have a problem with the units in Newton's Gravitational constant?
http://www.google.com/search?q=G
[tex]\mbox{gravitational constant}\ G = 6.67 \times 10^{-11}\rm m^3 kg^{-1} s^{-2} [/tex]
 
  • #75
free_mind said:
r^2 is geometrically explainable
How? What physical significance does it have?
...but c^2 with it's extraordinary units it's not so easy to explain.
There is nothing at all extrordinary about the units of C^2. They appear in many, many different equations -from other kinetic energy equations, to the many forms of Bernoulli's equation. Do you have a similar problem accepting Bernoulli's equation?
If you read all my posts you will understand that they are different from the first. I inserted lots of threads, but you fixed you atention at the first one;
Yes, I know - the reason I'm focusing on that first post is that you appear to be unwilling to acknowledge the error! Others, too. You're ducking and weaving, trying to press your point witout acknowledging the errors in it as they are addressed - quickly dropping each point and moving to the next as its flaws are exposed.
That means that you don't agree with my affirmation?
You said you had examples - are you willing to provide any or not?

Let me give you one: black holes. Black holes were derived mathematically and were peculiar enough that people doubted their existence. But not anymore. Today, their existence is an observational fact. However, it would not be a surprise to me at all if you didn't accept that...
This is a common knowledge between mathematicians...
As a matter of fact, there is considerable debate over the physical reality of mathematical derivations, with virtually all of the difficulty coming from people who don't want to accept the physical reality of what is being described in the equations - ie, you in this thread. Much of it had to do with QM - QM made a great many people uncomfortable about its implications. The debate largely died down because every time a new piece of evidence was found, it confirmed the physical reality of the equations.

Today, largely because of the success of QM, when new implications of a theory derived mathematically, they are not as easily dismissed as mathematical peculiarities because of discomfort.
 
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  • #76
free_mind said:
It seems that anything multiplied by mass in Einstein formula will have a physical meaning, probably even potatoes :)

Ok honestly, if you don't want an education in science, you do not have to post here.
 
  • #77
Did you understand that I was talking about the nuclear bombs?

Yes it is the same principal! There are fusion (like the process above) and fission bombs, you never stated which. It doesn't matter anyways because they both follow the exact same principal! Fusion is the opposite of fission.

Have you the slightest clue how a nuclear bomb works?
 
  • #78
robphy said:
I'm curious.
Do you also have a problem with the units in Newton's Gravitational constant?
http://www.google.com/search?q=G
[tex]\mbox{gravitational constant}\ G = 6.67 \times 10^{-11}\rm m^3 kg^{-1} s^{-2} [/tex]

I don't have only a problem, I have several problems. Let's see why the Gravitational constant it's not sacred. That's why there are another methods to mesure gravity.

It is readily apparent that the current gravitational constant is not a tangible physical concept as demonstrated by its units of measure which are currently mandatory for the law of universal gravitation to yield the correct units for force.

Gravity as detailed in the Laws of Space and Observation does not exist as a direct force but rather as the result of the pressure exerted by "Space" on the matter/energy that is displacing it. Gravity is equal to the Relative Space Warp (the RSW = APD/360 - sin(AGI) x APD/360 and is the corrected angle of photon deviation at a certain radius around a mass divided by 360) multiplied by the Space Constant (the SC is the pressure exerted by Space [gravity] at the horizon of a black hole and is equal to 2.0E8 m/s2).2 This will yield a value for gravity in m/s2. In the Laws of Space and Observation, G does not exist. Some may say that the SC is still a constant, but unlike G, it is a real value with meaning.

CoData now lists G = 6.6742E11Nm2/Kg2 and assigned a quite conservative uncertainty of 0.015%. Comparing this constant to other well known units of physics, the fractional uncertainty in G is still thousands of times larger. As a result, the mass of the Earth, the sun, the moon and all celestial bodies cannot be known to an accuracy greater than that of G, since all these quantities have been derived from the experimental G. The units of G are m3/Kg/sec2, so any error in the Kg unit will show up as an error in G. An uncertainty of 0.015% might seem quite small, but when applied to masses under consideration, for example Earth's mass with a nominal mass of 5.972E24 Kg, it means that the actual mass could be higher by as much as 8.958E20 kg!, and that's why the mass of Earth can only be given to three decimal places.
 
  • #79
This thread is 6 pages too long.
 
<h2>1. Why is the speed of light squared in E=mc^2?</h2><p>The speed of light squared, or c^2, is included in the famous equation E=mc^2 because it represents the conversion factor between mass and energy. This means that mass and energy are essentially interchangeable, and the speed of light squared is the constant that relates the two.</p><h2>2. How did Einstein come up with the equation E=mc^2?</h2><p>Albert Einstein developed the equation E=mc^2 as part of his theory of special relativity in 1905. He realized that the speed of light is a fundamental constant in the universe and that it has a direct relationship to mass and energy. Through mathematical calculations and thought experiments, he derived the equation that revolutionized our understanding of the relationship between mass and energy.</p><h2>3. What does the speed of light squared represent in E=mc^2?</h2><p>The speed of light squared, or c^2, represents the amount of energy that is equivalent to a given amount of mass. This means that if you were to convert a certain amount of mass into energy, you would need to multiply it by the speed of light squared to determine the amount of energy produced.</p><h2>4. Is the speed of light squared a constant or a variable in E=mc^2?</h2><p>The speed of light squared, or c^2, is a constant in the equation E=mc^2. This means that it does not change and has the same value in all situations. The speed of light itself, however, is a variable and can change depending on the medium it is traveling through.</p><h2>5. Can E=mc^2 be applied to everyday situations?</h2><p>Yes, E=mc^2 has practical applications in everyday situations. For example, it is used in nuclear energy and nuclear weapons, where mass is converted into energy. It is also used in medical imaging techniques, such as PET scans, which rely on the conversion of mass into energy to create images of the body's tissues and organs.</p>

1. Why is the speed of light squared in E=mc^2?

The speed of light squared, or c^2, is included in the famous equation E=mc^2 because it represents the conversion factor between mass and energy. This means that mass and energy are essentially interchangeable, and the speed of light squared is the constant that relates the two.

2. How did Einstein come up with the equation E=mc^2?

Albert Einstein developed the equation E=mc^2 as part of his theory of special relativity in 1905. He realized that the speed of light is a fundamental constant in the universe and that it has a direct relationship to mass and energy. Through mathematical calculations and thought experiments, he derived the equation that revolutionized our understanding of the relationship between mass and energy.

3. What does the speed of light squared represent in E=mc^2?

The speed of light squared, or c^2, represents the amount of energy that is equivalent to a given amount of mass. This means that if you were to convert a certain amount of mass into energy, you would need to multiply it by the speed of light squared to determine the amount of energy produced.

4. Is the speed of light squared a constant or a variable in E=mc^2?

The speed of light squared, or c^2, is a constant in the equation E=mc^2. This means that it does not change and has the same value in all situations. The speed of light itself, however, is a variable and can change depending on the medium it is traveling through.

5. Can E=mc^2 be applied to everyday situations?

Yes, E=mc^2 has practical applications in everyday situations. For example, it is used in nuclear energy and nuclear weapons, where mass is converted into energy. It is also used in medical imaging techniques, such as PET scans, which rely on the conversion of mass into energy to create images of the body's tissues and organs.

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