Calculating Energy Equivalent of 1 Gram Mass

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Homework Help Overview

The discussion revolves around calculating the energy equivalent of a mass of one gram using the equation E = mc², focusing on unit conversions and the proper expression for mass in the equation.

Discussion Character

  • Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants explore the relationship between mass in grams and kilograms, questioning how to properly substitute values into the equation to yield energy in Joules. There is also a focus on understanding the units involved in the equation and ensuring they align correctly.

Discussion Status

Participants are actively engaging with the concepts, clarifying the units for mass and energy. Some have provided insights into the dimensional analysis of the equation, while others express confusion about the correct substitutions and unit conversions. There is no explicit consensus, but productive dialogue is occurring around the topic.

Contextual Notes

There is an emphasis on the need for clarity regarding the conversion of grams to kilograms and the proper application of the speed of light in the equation. Participants are also reflecting on their understanding of energy units and the implications of mass-energy equivalence.

bkelly
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what is the equation for mass when calculating its energy equivalent? For one gram of mass E = mc(squared) would be

E = m * ( 9*10 to the 16th meters per second squared)

what are the values I put in for m being 1 gram such that the end result will be energy. I have googled this but get all kinds of nonsense other that I want.

Thanks.
 
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In the equation:

[tex]E = mc^2[/tex]

E is in Joules, m is in kilograms, and c is the speed of light in meters per second (~300,000,000 meters/sec).
 
I understand the mass is in kilograms (1000 grams) but what is the exact expression I put into the equation to get this thing to work out to the right units for energy:

E = m * ( 9*10 to the 16th meters per second squared)

for 1 kilogram, what is the full text to be used for replacing m?

E = (1 kilogram) * ( 9*10 to the 16th meters per second squared)
I just don't get this to work out to the right units.

Thank you
 
If we check out the dimensions on the rhs of the eqn, mc², we get

[kg][m²/s²] = [kg.m/s²][m] = [N][m] = [J]

where we used units of kg for the mass and m/s for the speed.
We end up with the units/dimensions of mc² being equivalent to Joules, which is work done or energy.

So, if the mass that you are interestred in is, m = 1 kg, then the energy of this mass is,

E = mc²
E = 1[kg]*(3*10^8)²[m²/s²]
E = 9*10^16 [kg.m/s²][m]
E = 9*10^16 [J]
============

Hmm, just noticed. You have the speed squared as metres per second squared. That should have been metres squared per second squared.
 
I think I understand what you are saying. It seems I was putting too much into the definition of a (kilo)gram. So to put this in other words, if we could translate one kilogram of mass into its energy equivalent, we could get 9 * 10^16 watt seconds of electric power. Thats a lot of power.

Yes, I did forget that meters squared.

Thanks for your help.
 
I would just say, watt seconds of power. I don't think you need to specify it as electric.

And yes, you do get a lot of power when you convert mass to energy.
 

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