$${\Delta E_{soojus} = W – (\frac{1}{2}mv^2 – \frac{1}{2}mv_0^2) = W – \frac{1}{2}m(v^2 – v_0^2) \\ = 20\, \mathrm{J} – \frac{1}{2}(14\, \mathrm{kg})[(0,20\, \mathrm{m/s})^2 – (0,60\, \mathrm{m/s})^2] \\ = 22,2\, \mathrm{J} \approx \underline{\underline{22\, \mathrm{J}}}}$$