$${W = Fd \cos \phi = 50mgd \cos \phi \\ = (50)(80\, \mathrm{kg})(9,8\, \mathrm{m/s^2})(45\, \mathrm{m}) \cos 0^{\circ} \\ = 1,8 \times 10^6\, \mathrm{J} \approx 2\, \mathrm{MJ}}$$