Hydraulics And Fluid Mechanics MCQ Questions & Answers | Civil Engineering

Buoyant force is the upward force exerted by a fluid on a submerged or partially submerged object.

This force acts vertically upward through the center of buoyancy, which is the centroid of the displaced fluid volume.

Since pressure in a fluid acts equally in all directions at a given depth, any horizontal forces acting on opposite sides of the object cancel each other out.

As a result, the horizontal components of the pressure forces balance out, and only the vertical component remains as the net buoyant force.

Conclusion: The horizontal component of buoyant force is zero, making Option C the correct answer.

Surface tension is a measure of force per unit length, the SI units for which is newtons per meter (N/m).

When fluid flows through a pipe, energy is lost due to friction, and this loss is called the head loss.

The power transmitted by the fluid depends on the head available after accounting for this frictional loss.

Let the total head supplied be H, and let the head loss due to friction be h_f.

Then, the head available for power transmission = H – h_f

Horsepower transmitted ∝ (H – h_f) × flow rate, and flow rate itself ∝ √(H – h_f)

Hence, horsepower transmitted is proportional to (H – h_f)^1.5

To maximize power, differentiate the expression and solve: the power transmitted is maximum when h_f = H / 3

That means, head loss due to friction is one-third of the total head supplied.

Therefore, the correct answer is: Option A — 1/3