\begin{align} \text{Per tal de calcular la energia mecànica hem de} :&\cssId{Step1}{E_{mec} =E_{p} }\\[3px] &\cssId{Step2}{E_{mec} = mg\Delta h}\\[3px] &\cssId{Step3}{E_{mec} =1000 * 9,807 * (20-0) }\\[3px] &\cssId{Step4}{E_{mec} = 196,1 kJ}\\[3px] \end{align}