6.For laminar flow in circular pipes, the Darcy's friction factor f is equal to

7.Drag force is a function of i) projected area of the body ii) mass density of the fluid iii) velocity of the body The correct answer is

8.Surge wave in a rectangular channel is an example of i) steady flow ii) unsteady flow iii) uniform flow iv) non-uniform flow The correct answer is

9.Two pipes of same length and diameters d and 2d respectively are connected in series. The diameter of an equivalent pipe of same length is

10.The wake