# What is relativity of mass?

## What is the relativity of mass?

If an object moves at velocity v with respect to an observer at rest, it's mass at motion will be 1 / √(1-v2/c2) times the mass of the object at rest. This is called the relativity of mass.

The relativity of mass refers to the concept in Einstein's theory of special relativity that mass is not an absolute scalar quantity, but is instead relative to the observer's state of motion. According to this theory, an object's mass depends on its velocity relative to the observer. As an object moves faster, its mass increases, and as it approaches the speed of light, its mass approaches infinity. This is due to the fact that the energy contained in a moving object is proportional to its mass, and as the object moves faster, its energy increases. The relativity of mass is an important concept in physics and has important implications for our understanding of the universe, including the behavior of particles at high speeds and the behavior of matter in extreme conditions.