Work Energy And Power

A force \(\mathbf{F}=-k(y \hat{\mathbf{i}}+x \hat{\mathbf{j}})\) where \(k\) is a positive constant, acts on a particle moving in the \(x y\) plane. Starting from the origin, the particle is taken along the positive \(x\)-axis to the point \((a, 0)\) and then parallel to the \(y\)-axis to the point \((a, a)\). The total work done by the force on the particle is