Mass versus relativistic and rest masses

摘要

The concept of relativistic mass, which increases with velocity, is not compatible with the standard language of relativity theory and impedes the understanding and learning of the theory by beginners. The same difficulty occurs with the term rest mass. To get rid of relativistic mass and rest mass it is appropriate to replace the equation Е=mc~2 by the true Einstein's equation Е_0=mc~2, where E0 is the rest energy and т is the mass.