Does it mean that as you increase the energy of a particle

[Helicobacter]

Does it mean that as you increase the energy of a particle, its mass will increase? Or, that for any given particle there is a certain container of certain mass/energy and part of that quantity is allocated to energy and the other to mass. In the latter case, could you not make a transistor out of this where you encode 0/1 states to certain mass/energy distributions?

On an simple, intuitive level (I'm a physics layman):

Why does it happen to be related by exactly the speed of light squared?

How does this equation follow from the simple statement: The speed of light is the same in all inertial reference frames?

 

[jfy4]

The equation comes in the form
$$E=\frac{m_0 c^2}{\sqrt{1-\left(\frac{v}{c}\right)^2}}$$
When things aren't moving, or are moving slowly this just becomes $E=m_0 c^2$. In general, it was considered as an answer to the question: "Does the inertia of a body, depend upon it's energy content?" But the idea of relativistic mass, mass that changes depending on velocity, is no longer in vogue.

 

[Helicobacter]

Mass–energy equivalence does not imply that mass may be "converted" to energy, and indeed implies the opposite.

answers the first question