Answer
$2200J=2.2kJ$
Work Step by Step
According to the work-energy theorem, work is equal to the change in kinetic energy. Since the object is initially at rest, the change in kinetic energy is equal to the final kinetic energy. This means that $$W=\frac{1}{2}mv^2$$ Substituting known values of $m=73kg$ and $v=7.7m/s$ yields a work of $$W=\frac{1}{2}(73kg)(7.7m/s)^2=2,200 J=2.2kJ$$