I just need to get part B for this, I understand how to get part A

1. Two immiscible, incompressible, viscous fluids having different viscosities are contained between two infinite, horizontal, parallel plates. The bottom plate is fixed, and the upper plate moves with a constant velocity U. Each liquid layer has a thickness of h. The motion of the fluid is caused only due to the motion of the top plate; there is no pressure gradient in the x-direction. Assuming the flow is laminar, (a) develop an expression for determining the velocity of the fluid at the interface between the fluids (Hint: final answer should only include the variables U,1, and 2 ). (b) Assuming that the velocity of the top plate is 2cm/s and the top fluid is toluene (v=0.68smm2,SG=0.867) and the bottom fluid is water (v=1smm2), create a plot of the velocity profile with the height (measured from the bottom plate) on the y-axis, and the velocity on the x-axis. (Hint: the fluid velocities and shearing stresses should be continuous across both fluids including across the interface between the fluids.) (u(y=h)=0.742scm)