From Mechanics

\displaystyle \begin{align} & {{\mathbf{u}}_{W}}=\mathbf{i},\ {{\mathbf{v}}_{W}}=0\textrm{.}8\cos 60{}^\circ \mathbf{i}+0.\textrm{.}8\sin 60{}^\circ \mathbf{j} \\ & m(\mathbf{i})=m(0\textrm{.}8\cos 60{}^\circ \mathbf{i}+0\textrm{.}8\sin 60{}^\circ \mathbf{j})+m{{\mathbf{v}}_{R}} \\ & {{\mathbf{v}}_{R}}=(1-0\textrm{.}8\cos 60{}^\circ )\mathbf{i}-0\textrm{.}8\sin 60{}^\circ \mathbf{j} \\ & =0\textrm{.}6\mathbf{i}-0\textrm{.}6928\mathbf{j} \\ & {{v}_{R}}=\sqrt{{{0\textrm{.}6}^{2}}+{{0\textrm{.}6928}^{2}}}=0\textrm{.}916\text{ m}{{\text{s}}^{\text{-1}}} \end{align}