# Relativistic momentum

1. Sep 23, 2011

### khil_phys

The relativistic momentum is given by p=mvγ, where Y is the Lorentz factor and m is the rest mass of the body.
My question is that if we are considering the momentum of the body at relativistic speeds, shouldn't we also consider the relativistic mass of the body?

2. Sep 23, 2011

### CompuChip

That's exactly what you are doing. It is just p = mr v, where $m_\mathrm{r} = \gamma m_0$ is the relativistic mass (in the direction of v).

3. Sep 23, 2011

### jfy4

Compu is right. Although you will find other physicists prefer to write the invariant rest mass, $m_0$, and $\mathbf{u}=\gamma (c,\vec{v})=\gamma\mathbf{v}$. You could find either of these in the various texts on relativity.