A block that is a mm square slides across a flat plate on a thin film of oil. Th

Question

A block that isamm square slides across a flat plate on a thin film of oil. The oil has viscosity ?and the film ishmm thick. The block of mass M moves at steady speed U under the influence of constant force F. Indicate the magnitude and direction of the shear stresses on the bottom of the block and the plate. If the force is removed suddenly and the block begins to slow, sketch the resulting speed versus time curve for the block. Obtain an expression for the time required for the block to lose 95 percent of its initial speed.

Explanation / Answer

F = (mu) x A x dU/dY

here a = area = 1mm x 1mm = 1mm^2 = 10^-6 m^2

du = U

and dY = h mm = h x 10^-3 m

mu = coefficient of viscosity

so, F = mu x (10^-6) x U/(h x 10^-3) N

b)

time required = t = 0.05 U.M / (F)

sorry cant upload the sketch. pls rate sketch is straight line passing thru origin with slope = 0.05M/F

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.