# E=mc^2

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$E=MC^2$

$1 kg * C^2 = 8.98755179 * 10^{16} joules$

What is $8.98755179 * 10^{16} joules$ used for?

Is this just a conversion from mass to energy or energy needed to accelerate it to a certain speed in a given time?

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it's the energy that would be released in a matter to energy conversion. if %100 efficient and everything goes well.

the energy needed to accelerate something is it's mass times the acceleration

Merged post follows:

Consecutive posts merged

check out this thread for a tour of different conversions

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That's how much energy would be released if you added 0.5 kg of matter with 0.5 kg of its antimatter counterpart. But there's nothing magical about 1 kg — that number is arbitrary. c^2 is a conversion factor.

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Of course, we also have f=ma. Thanks folks, your only easy question this week.

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the energy needed to accelerate something is it's mass times the acceleration

That's the force necessary to cause an object to accelerate at a given rate. 'The energy required to accelerate something' is also misleading. The energy required to accelerate something up to a given velocity $v$ is $\frac{1}{2}mv^2$, or the energy required to move an object a distance $d$ while accelerating at a rate $a$ is $ma\cdot d$.

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It means that mass is another kind of energy. However, the energy is hard to be released. This is the basic principle for fission and fusion reaction. There is a mass difference between the reactants and the products. Then huge amount of energy is released. The problem is that we have to provide large amount of energy to excite the reaction. Also once the reaction occurs, ie exploses and the reaction rate is hard to control. That is the reason why they are used as bombs.

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... However, the energy is hard to be released...

I agree. A one kilogram rock equivalent to $8.98755179 * 10^{16} joules$. As mentioned, antimatter is our only hope.

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It means that mass is another kind of energy.

what kind of energy exactly?

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the matter can be converted into any kind of energy.

think about what energy is on a fundamental level, its either kinetic or potential, there is no energy particle.

in the case where your converting some mass into energy most of the time (all of the time?) the energy goes into the kinetic energy of the products.

for instance in fission the energy goes into the kinetic energy of all of the products, fission fragments, gamma rays, and neutrons.

hmm, swansont by any chance do you know if there is a situation where the energy released by the conversion of mass would go directly to potential energy?

I could think that there is a reaction where a particle decays into two lighter particles which are mutually attracted to each other, however I'm not sure if such a thing exists.

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• 1 month later...

Well it depends a bit on how you construct your instrument which converts it so.

(but generally speaking , the resultant energy from such a conversion, artificial or natural, is electromagnetic energy). (light, heat, gamma rays, etc etc... but also some other particles)

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