Question

can maas be variable? if yes then how.Also mass can be negative?

Answer 1

Yes ...because ...a variable-mass system is a collection of matter whose mass varies with time. It can be confusing to try to apply Newton's second law of motion directly to such a system.


negative mass is matter whose mass is of opposite sign to the mass of normal matter, e.g. −1 kg.[1][2] Such matter would violate one or more energy conditions and show some strange properties, stemming from the ambiguity as to whether attraction should refer to force or the oppositely oriented acceleration for negative mass.


mark this answer as brainlest please....

Answer 2

Answer

Before I answer your question, I would like to start by giving a more explicit version of Einstein's famous equation, E = mc2. It is commonly written as follows: 
(Check the image)
where E is the energy of the object in question, m0 is its rest mass, c is the speed of light, and gamma is a numerical factor that depends on velocity. The expression for gamma is 
(check the second image)

where v is the object's velocity. At very small velocities, gamma is approximately equal to one. At velocities near the speed of light, gamma becomes larger and larger (try plugging in some numbers and see). Already you can see why a massive particle can never travel at the speed of light: it would take an infinite amount of energy, and no engine in the universe can provide that sort of power! 

Now I will answer your question. Einstein interpreted the combination gamma * m0 to be the mass of an object in motion. This is why the equation is usually quoted simply as E = mc2. The equation relating mass to velocity is 
(Check the third image)

Mass, like gamma, grows with velocity. As the object approaches the speed of light, the mass approaches infinity! 

I should give a word of caution: many physicists simply call m0 the mass, dropping the distinction between the rest mass and Einstein's velocity-dependent mass. So be careful to note which definition is being used! 



The mass of something can never be negative as this may violate a no. of laws mostly regarding the Energy of the body..