Answer
$K = 2.7\times 10^{15}~J$
Work Step by Step
We can find the kinetic energy of the object:
$K = (\gamma-1)mc^2$
$K = (\frac{1}{\sqrt{1-\frac{v^2}{c^2}}}-1)mc^2$
$K = (\frac{1}{\sqrt{1-\frac{(1.80\times 10^8~m/s)^2}{(3.0\times 10^8~m/s)^2}}}-1)(0.12~kg)(3.0\times 10^8~m/s)^2$
$K = (1.25-1)(0.12~kg)(3.0\times 10^8~m/s)^2$
$K = 2.7\times 10^{15}~J$
