A bearing can be modelled as two parallel plates moving in opposite directions with velocities $3$ and $1.$ The plates are separated by a gap of $6$ mm which is filled with light oil which has a dynamic viscosity of $0\mathrm{.}1$ Nsm$-2.$ The oil flows into the gap such that there is a pressure drop of $30$kPa per meter. What is the maximum shear stress $($in Pa$)$ experienced at the plates?