A $2\mathrm{.}52$ kg block starts from rest on a rough inclined plane that makes an angle of $60\mathrm{.}0$ with the horizontal. The coefficient of kinetic friction is $0\mathrm{.}250.$ As the block goes $2\mathrm{.}76$ m down the plane, the mechanical energy of the Earth$-$block system changes by

$$ J