Answer
We use the conversion:
$1$ GeV= $1.6\times 10^{-10}$ J
The final answer for the speed is $2.35\times 10^8$ m/s.
Work Step by Step
The mass of an antiproton equals the mass of a proton,( $m_p$) which is $1.673\times10^{-27}$ kg.
Momentum of antiproton = $p=1.19\hspace{2mm}$ GeV/c
We know $p=\gamma m_p v$ where $v$ is the speed of antiproton. This is equation 1 (say).
Lorentz factor= $\gamma=\Large \frac{1}{\sqrt{1-(\frac{ v}{c})^2}}$
$c=3\times 10^8$ m/s
Thus we have in equation 1:
