# when a body travels with speed nearly equal to light's speed we say that its mass becomes infinity but how and in what form mass is created i maenwhat is created an electron, proton, quatrz, neutron what thing is created that adds up to mass of body?

### Asked by upmaniousagarika | 8th Jun, 2016, 11:29: PM

Expert Answer:

### The concept of mass in relativity is different than the concept in Newtonian mechanics.
When we say that a body is approaching the speed of light, its acceleration is high and so the force on it is high.
From Newton's law, F = ma will give m approaching infinity.
However, in relativity things work differently. For an object to travel at speed of light, infinite amount of energy is needed.
From einstein's relation energy and mass are interconvertible. So, one can say that mass approaches infinity.
But, this is for another object which is observing the body travel at the speed of light.
For the body which is travelling, it is relatively stationary with itself. Hence, its mass will be invariant and there will be no addition to its mass.
So, all in all there is no addition of mass to any object. Its just that since the object is travelling at such a high speed, an observer feels that the body has attained infinite mass and hence infinite energy.

### Answered by Romal Bhansali | 10th Jun, 2016, 09:41: AM

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