A $2\mathrm{.}37$kg$2\mathrm{.}37$kg block starts from rest on a rough inclined plane that makes an angle of $60\mathrm{.}060\mathrm{.}0$ with the horizontal. The coefficient of kinetic friction is $0\mathrm{.}2500\mathrm{.}250.$ As the block goes $2\mathrm{.}75$m$2\mathrm{.}75$m down the plane, the mechanical energy of the Earth$-$block system changes by