# Whenever we increase the velocity of a particle, the mass of he particle also

• aayushmittal
The equivalence of the two objects is a mathematical concept, but the two objects are not the same. So, too, mass and energy are equivalent, but they are not the same. The speed of light is invariant under the action of a force. If you increase the velocity of a particle, the mass of the particle also increases, but the speed of light is still invariant. This means that you can't travel faster than the speed of light, even if you increase the mass of the particle.f

#### aayushmittal

I read somewhere than whenever we increase the velocity of a particle, the mass of he particle also increases. I also read that it is impossible reach the speed of light as the mass of the particle, just before reaching the speed of light, will become infinite (not infinite but very large) and a lot of force will be needed to increase the speed further which will only result in more increase in mass. Now, i have the following 2 questions-

1. Why do mass go on increasing? and-
2. what if we consider mass less particles? Which there will an increase in mass too? If no, then why can't they achieve the speed of light?

2. what if we consider mass less particles? Which there will an increase in mass too? If no, then why can't they achieve the speed of light?

Hey, welcome to the forum. I would suggest that in future you think of a meaningful title for your posts, since that way you will attract more people who are interested in the subject you are asking about. "Please see below" is not helpful.

Massless particles ALWAYS travel at the universal speed limit (the same speed that light travels at).

2. what if we consider mass less particles? Which there will an increase in mass too? If no, then why can't they achieve the speed of light?
Massless particles (particles with zero invariant mass) already move at the speed of light.

1. Why do mass go on increasing?

The answer to your first question should answer an important distinction: the real mass of the particle is not increasing.

There is a danger of equivocation over 'equivalence' and 'sameness' in Einstein's famous equation. What is increasing is the total energy of the system. By analogy, we can say that dollar and a yen can be related in an equation (using the exchange-rate as a constant). But a dollar is not a yen.