Question

Which one of the follflowing is correct?

(a) the frictional resistance depends on the nature of the surface area of contact

(b) the frictional resistance is independent of the nature of the surface area of contact

(c) the frictional resistance depends on the nature of the surface area of contact for laminar flows but is independent of the nature of the surface area of contact for turbulent flows

(d) the frictional resistance is independent of the nature of the surface area of contact for laminar flows but depends on the nature of the surface area of contact for turbulent flows

I have been asked this question during an interview.

The query is from Loss of Energy in Pipes in section Flow Through Pipes of Fluid Mechanics

Answer 1

Right option is (d) the frictional resistance is independent of the nature of the surface area of contact for laminar flows but depends on the nature of the surface area of contact for turbulent flows

Explanation: According to the laws of fluid friction, the frictional resistance is independent of the nature of the surface area of contact for laminar flows but depends on the nature of the surface area of contact for turbulent flows.