Answer
$\gamma = 2 $
Work Step by Step
From part (a), we knew that $\beta = 0.866$.
The formula for lorenz factor is $\gamma = \frac{1}{\sqrt (1-(\frac{v}{c})^2)}$.
Substituting the above value of $\beta$ in the formula and solving:
$\gamma = \frac{1}{\sqrt (1-\beta^2)}$
$\gamma = \frac{1}{\sqrt (1-0.866^2)}$
$\gamma = 2 $
