# What units is E=MC measured in?

• scupydog
In summary, the equation E=mc² uses the units of energy for E, mass for m, and speed for c. These units can be adjusted to fit any preferred measurement system, but the energy units will come out as the natural units for that system. For example, in SI units, E would be in joules, m in kilograms, and c in meters per second. However, other units such as eV and eV/c² are often used in particle physics. It is important to ensure that the units are consistent in order to get the correct value for energy.
scupydog
Hi all could anyone tell me what units are used in the equation E=MC.

Thx, Dave.

J, kg, m/s

Last edited:
but the equation is wrong.. E = mc^2 it should be ;-)

scupydog said:
Hi all could anyone tell me what units are used in the equation E=MC
E is in units of energy, m in units of mass, and c in units of speed. mgb_phys already gave the standard SI units, but you can use any units that you prefer. For particle physics they often use eV (electron volts) for E and eV/c² for m and, uhh, c for c.

DaleSpam said:
but you can use any units that you prefer.
As long as the energy is in the natural units for the speed and mass - otherwise you need another proportionality constant.

That does mean the the "firkin furlong2 fortnight-2" is a natural unit of energy.

mgb_phys said:
J, m, m/s

what does the m for stand for ?

malawi_glenn said:
but the equation is wrong.. E = mc^2 it should be ;-)

sry that's what i should have typed.

scupydog said:
what does the m for stand for ?
sry that's what i should have typed.

Sorry I meant to type kg for mass
As DaleSpam said you can use any units you want for mass and speed but then the units of energy come out as the natural units for that measuerement system.
With SI (metric) it's easier, you could use lbs for the mass, mph for the speed of light and BTU for the energy but you would need another constant in front of the m to get the value right - it just happens that for kg / m / s the constant is 1.

## 1. What is the equation E=MC used for?

The equation E=MC is used to calculate the relationship between energy (E), mass (M), and the speed of light (C). This equation is a fundamental principle in physics and is also known as the mass-energy equivalence.

## 2. What are the units of energy in the equation E=MC?

The units of energy in the equation E=MC are joules (J). This is the standard unit of energy in the International System of Units (SI).

## 3. Are there any other units that can be used to measure E=MC?

Yes, there are other units that can be used to measure E=MC, such as electron volts (eV) or ergs (erg). However, joules are the most commonly used unit for energy in this equation.

## 4. Can E=MC be measured in terms of weight or mass?

No, E=MC cannot be measured in terms of weight or mass. Energy and mass are two different physical quantities and cannot be converted into each other. The equation E=MC simply shows the relationship between the two quantities.

## 5. Is the speed of light always measured in meters per second (m/s) in the equation E=MC?

Yes, the speed of light is always measured in meters per second (m/s) in the equation E=MC. This is the standard unit for measuring the speed of light, and it is used consistently in the equation to maintain accuracy and consistency.

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