## Rest Mass v. Movement

$\lambda=\frac{h}{p}$

Ashita Tanwar 3H
Posts: 30
Joined: Fri Sep 28, 2018 12:23 am

### Rest Mass v. Movement

Do objects that have no "rest mass" have mass when they are moving? Or do they just never have mass? How can the mass of an object change depending on its movement?

Aaron Ang 4H
Posts: 30
Joined: Fri Sep 28, 2018 12:28 am

### Re: Rest Mass v. Movement

It depends on the object that is moving. According to Einstein's theory of special relativity, if the object with no rest mass is traveling closer to the speed of light, the mass increases. As an object approaches the speed of light, its mass approaches infinity as well

caseygilles 1E
Posts: 73
Joined: Fri Sep 28, 2018 12:18 am

### Re: Rest Mass v. Movement

No, photons do not gain mass as they move faster and faster. They do however have a relativistic mass based on their energy. Since a massless particle like a photon has energy it therefore also has momentum even though it has no rest mass. This does NOT mean that as particle move closer to the speed of light their mass approaches infinity as said on this thread. That is not true. I don't believe masses change with movement, they just have momentum because of kinetic energy and the effects of energy bending space-time.