A block of mass $1 \mathrm{kg}$ is pushed up a surface inclined to horizontal at an angle of $60°$ by a force of $10 \mathrm{N}$ parallel to the inclined surface as shown in figure. When the block is pushed up by $10 \mathrm{m}$ along inclined surface, the work done against frictional force is : $\left[g=10 \mathrm{m} {\mathrm{s}}^{-2}\right]$