Question

who mass increase when speed increase​

Answer 1

Answer:

Advertisement. So when we think of mass as energy, we can begin to understand why an object will increase its 'mass' as it speeds up. As an object increases in speed, so does the amount of energy that it has, this energy is what we refer to as 'the increase in mass' (just remember, this is inertial mass).

Answer 2

Mass doesn't actually increase. The amount of stuff in the material doesn't increase with speed. Extra atoms don't suddenly appear. Atoms don't become bigger or gain extra sub atomic particles. The amount of stuff in the material doesn't increase with speed.