144000 J
the kinetic energy formula is KE=0.5xmassxvelocity^2
the mass is 2x10^3 kg which is also 2000kg
the velocity is the speed in the question which is 12m/s
therefore, you sub in those values into the formula
which should look like this:
0.5x2000kgx12^2
which equals to 144,000 J
:D