Explanation: Viscosity is the internal friction of a fluid in motion. It is the property by the virtue of which the relative motion between two adjacent fluid layers is opposed.

Explanation: Pressure force is surface force.

Explanation: Due to constant temperature, pressure variation for compressible fluid is maximum for isothermal process.

Explanation: We balance the moment in order to calculate the position of centre of pressure.

Explanation: Absolute zero pressure is the reference used for the measurement of absolute pressure. Absolute zero pressure is possible (theoretically). Hence, 0 and positive values are possible, but a negative value is impossible.

Explanation: When the weight distribution is around the lower part, the centre of gravity is at lower portion and hence below the centre of buoyancy which is condition for stable equilibrium.

Explanation: Continuity equation must be perfunctorily satisfied while dealing with fluid flow problems.

Explanation: Fluid flow is laminar as it is assumed to be incompressible and Newtonian. The flow is laminar through the pipe of constant cross section. Thus, there is no acceleration of fluid in the pipe. Therefore, Hagen-Poiseuille assumed that fluid flow is laminar.

Explanation: Circular pipes have a diameter treated in a round manner. For a fluid flow which is laminar head loss is directly proportional to the fluid velocity. Thus, friction factor is inversely proportional to its velocity. Therefore, the correct option is ‘64/Re’.

Explanation: External diameter is not a global parameter. It is one of the most essential pipelining parameters. It helps in determining the type of pipe and material to be used for the same.

Explanation: Dimensional analysis is a process which is used to determine physical parameters that influence the fluid flow. The analysis is based on the fundamental units. The fundamental units are mass, length and time.

Explanation: Dynamic similarities have the same forces acting on them. That means, the ratios of all the forces acting on the fluid particles are constant. Also, the ratio of the forces acting on the boundary surfaces are also a constant.