The location of centre of pressure, which defines the point of application of the total pressure force on the surface, can be calculated by applying the principle of moments according to which “sum of the moment of the resultant force about an axis is equal to the sum of the components about the same axis”. The centre of pressure of a rectangular surface (of width ‘w’) immersed vertically in a static mass of fluid is at a depth of (where, y = depth of the liquid) ?

Related Mcqs:

1. Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid________________?

   A. Lies above the centroid of the plane surface
   B. Is independent of the specific weight of the fluid
   C. Is different for different fluids
   D. Is at the centroid of the plane surface

2. Bernoulli’s equation for fluid flow is derived following certain assumptions. Out of the assumptions listed below, which set of assumptions is used in derivation of Bernoulli’s equation? A. Fluid flow is frictionless & irrotational. B. Fluid flow is steady. C. Fluid flow is uniform & turbulent. D. Fluid is compressible. E. Fluid is incompressible ?

   A. A, C, D
   B. B, D, E
   C. A, B, E
   D. A, D, E

3. A rectangular surface 3′ × 4′, has the lower 3 edge horizontal and 6′ below a free oil surface (sp. gr. 0.8). The surface inclination is 300 with the horizontal. The force on one side of the surface is (where, y = specific weight of water) ?

   A. 39.6y
   B. 48y
   C. 49.2y
   D. 58y

4. Centre of pressure in an immersed body is ______________ the centre of gravity?

   A. Above
   B. Below
   C. At
   D. Either above or below; depends on the liquid density

5. The pressure drop per unit length of pipe incurred by a fluid ‘X’ flowing through pipe is Δp. If another fluid ‘Y’ having both the specific gravity & density just double of that of fluid ‘X’, flows through the same pipe at the same flow rate/average velocity, then the pressure drop in this case will be__________________?

   A. Δp
   B. 2Δp
   C. Δp2
   D. Δp/2

6. The ratio of width to depth for the most economical rectangular section in open channel flow is_________________?

   A. 0.5
   B. 1
   C. 1.5
   D. 2

7. In open channel flow in a rectangular channel, the ratio between the critical depth and the initial depth, when a hydraulic jump occurs is_________________?

   A. 0.5
   B. 0.84
   C. 1.84
   D. 1.25

8. If ‘x’ is the depth of flow in an open channel of large width, then the hydraulic radius is equal to________________?

   A. x
   B. x/2
   C. x/3
   D. 2x/3

9. For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the___________________?

   A. Square of the radial distance
   B. Radial distance linearly
   C. Inverse of the radial distance
   D. Elevation along vertical direction

10. The equivalent diameter for pressure drop calculation for a fluid flowing through a rectangular cross-section channels having sides ‘x’ & ‘y’ is given by_________________?

    A. 2xy/(x + y)
    B. xy/(x + y)
    C. (x + y)/2xy
    D. (x + y)/xy