• A thin 30-cm x 30-cm flat plate is pulled with a force F through a 3.6-mm-thick layer of oil (u= 0.01 Pa s). The oil is sandwiched between a fixed upper wall and a lower wall moving at 0.3 m/s while the plate moves at a steady velocity of 1 m/s.

•  a) Schematically draw the velocity profile in the oil and determine the positions, above the moving wall, where the velocity is zero. (6 points)

•  b) Sketch the drag forces by the oil on the upper and lower wall and the two sides of the plate. (4 points)

• c) What value for F is required to achieve the specified velocity? (6 points)

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