Question

The center of pressure of surface subjected to fluid pressure is the point
A) on the surface at which the resultant pressure acts
B) on the surface at which gravitational force acts
C) equal to volume of liquid displaced
D) none

Answer 1

Hint: The above problem can be explained by using the concept of the center of pressure. The center of pressure of a fluid system can be defined as the location in the fluid system at which the total pressure of the fluid system can be assumed to be act. The center of pressure of the fluid system varies with the shape of the fluid system.

Complete step by step answer:
The resultant pressure acts on the center of pressure of the surface, so the option (A) is correct.

The gravitational force acting on the surface is independent of the location of the center of pressure, so the option (B) is incorrect.

The center of pressure on the surface depends only on the moment of inertia and center of gravity and independent of the volume of the liquid displaced, so the option (C) is incorrect.

Additional Information: The total force acts on the center of pressure is given as:
$F = \rho gAh$
Here, $\rho $ is the density of the fluid
$g$ is the gravitational acceleration
$A$ is the area of the surface
$h$ is the distance of the center of gravity from the free surface of the fluid
The center of gravity of the fluid lies above the center of pressure of the fluid surface.

Note: The center of pressure and center of gravity is the different point in the fluid system. The total pressure of the fluid acts on the center of pressure and total weight of the fluid acts on the center of gravity of the fluid system.