If the mass of an object or system is a measure of its energy content, multiplied by speed of light squared, does it mean that the total potential energy of the rest mass of object or entire system can only be realized when velocity is similar to speed of light?
What I am looking for is a clear and simple explanation on the exact purpose 'c square' serves in this equation. I need to have a basic explanation suitable for a 10 year old without too many complicated Special Relativity equations.
What he understands is that $E = mc^2$ oblivious of the units of measurement.
Is this the way the equation was derived?
Work (W) is a measure of the energy (E) expended in applying a force (F) to move an object.
And, Work (W) is defined as force (F) times distance (D).
So $E = W = D * F$
And Force (F) is Mass (M) times Acceleration (A).
So, $E = D * M * A$
And Acceleration (A) is the rate at which the velocity (V) of the object changes over time.
So, A = Change in velocity / Time taken (T).
And V = Distance (D) / Time (T).
So, $Energy = Distance \times Mass \times ((Distance/Time)/Time)$, viz.,
$E = (M x D^2) / T^2$ or $Energy = Mass \times (Distance/Time)$ squared.
Since $D/T$ = Velocity or Speed
The potential Energy (E) of an object is made up of its mass times its velocity squared.
And since the object is at rest, and we are trying to obtain 'Potential Energy' (any type of stored energy), I guess we can mention here the 'Potential Velocity' which cannot exceed the universal constant 'c' representing 'speed of light'.
So, $E = mc^2$.
Is this understanding correct?