Polymer coating is to be done on a flat plate. If the thickness of the laminar boundary layer that occurs during the coating process at a distance of $0.6 \mathrm{~m}$ from the plate's front edge is $12 \mathrm{~mm},$ determine the free-stream velocity of this fluid. Take $v=4.68\left(10^{-6}\right) \mathrm{m}^{2} / \mathrm{s}$.