Answer
$\gamma = 1.08$
Work Step by Step
We can find the kinetic energy of the protons:
$K = q~\Delta V$
$K = (1.6\times 10^{-19}~C)(75\times 10^6~V)$
$K = 1.2\times 10^{-11}~J$
We can find the Lorentz factor $\gamma$:
$K = (\gamma-1)~m_0~c^2$
$\gamma = 1+\frac{K}{m_0~c^2}$
$\gamma = 1+\frac{ 1.2\times 10^{-11}~J}{(1.67\times 10^{-27}~kg)(3.0\times 10^8~m/s)^2}$
$\gamma = 1.08$
