A uniform force of $\left( {3\widehat i + \widehat j} \right)$ newton acts on a particle of mass 2 kg. Hence the particle is displaced from position $\left( {2\widehat i + \widehat k} \right)$ metre to position $\left( {4\widehat i + 3\widehat j - \widehat k} \right)$ metre. The work done by the force on the particle is