Information AboutMass-energy Equivalence |
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: E=mc&2 where
The conversion factor c2 is 89.88 PJ/kg = 21.48 Mt TNT per kg = 149.3 pJ/ U = 931.5 MeV/u. If the energy in the equation is Rest Energy then the Mass much be Rest Mass or Invariant Mass . See Mass for a discussion of the two types of mass in relativity theory. CONSERVATION OF MASS AND ENERGY With the concept of mass-energy equivalence, we combine together the Conservation Of Mass and the Conservation Of Energy , allowing mass to be converted to forms of active energy (such as kinetic energy, heat or light) while still retaining mass. (However such energy can easily be lost from a system, causing it to lose mass). Conversely, active energy in the form of kinetic energy or radiation can be converted to particles which have Rest Mass . The total amount of mass and energy in a closed system (as seen by a single observer) remains constant. Energy cannot be created or destroyed, and in all of its forms, trapped energy exhibits mass. In relativity theory, mass and energy are two forms of the same thing, and neither one appears without the other. FAST MOVING OBJECT A fast-moving object moving at near to the speed of light cannot be accelerated to, or faster than, the speed of light, regardless of how much energy we put into the system. As we apply a constant force on such an object, and hence do work on the object, its speed does not appear to increase by the amount specified by Ekinetic = 1/2 mv2. Instead, the energy provided to it continues to appear as mass, even as the rate of velocity increase nearly stops. The object's relativistic mass increases, in what is known as Mass Dilation . The relativistic mass of an object is expressed as a function of its relative speed to that of light. SEE ALSO EXTERNAL LINKS |
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