[MHalblaub]

Don't mix up

E = mc^2

with

m'=m / sqrt(1-v^2/c^2).

The second equation shows an increase of mass!

You don't produce more elementary particle by just heating something but you get more mass!

You need an linear accelerator to get new particle or fission or fusion to make radiation out of particle.

The first equation tells how big the amount of energy is for a non moving mass.

[WildTurkey]

The second equation shows an increase of mass!

The first equation shows an increase in mass as calculated by the energy converted.

The second equation shows an increase calculated from the change in velocity of the particles.

[WildTurkey]

The first equation [E=MC²] tells how big the amount of energy is for a non moving mass.

This equation serves as a way to calculate how much mass is converted to energy or energy to mass in a reaction.