TeX source:

\begin{aligned} P &=\frac{0.5(60.0 \mathrm{~kg})(2.00 \mathrm{~m} / \mathrm{s})^{2}+(60.0 \mathrm{~kg})\left(9.80 \mathrm{~m} / \mathrm{s}^{2}\right)(3.00 \mathrm{~m})}{3.50 \mathrm{~s}} \\ &=\frac{120 \mathrm{~J}+1764 \mathrm{~J}}{3.50 \mathrm{~s}} \\ &=538 \mathrm{~W} \end{aligned}