$${K_f = K_i + W = \frac{1}{2} mv_i^2 + W \\ = \frac{1}{2}(500\, \mathrm{kg})(4,0\, \mathrm{m/s})^2 + 1,18 \times 10^4\, \mathrm{J} \\ = 1,58 \times 10^4\, \mathrm{J} \approx \underline{\underline{16\, \mathrm{kJ}}}}$$