Day 39-Oct 29-worksheet-Btech-Pressure contd. & hydrostat forces

A differential U-tube manometer compares two points in a water line. The mercury (SG = 13.6) column shows a level difference of 0.18 m. Find the pressure difference between the two points in kPa. (Take ρ_water = 1000 kg/m³, g = 9.81 m/s².)

(a)  

A vertical rectangular plate (height 2.0 m, width 1.5 m) has its top edge 1.0 m below a free water surface. Find (i) the resultant hydrostatic force, and (ii) the depth of the centre of pressure below the free surface.

(a)  

A horizontal circular hatch of diameter 1.0 m is located at a uniform depth of 5.0 m below the free water surface. Find the resultant hydrostatic force and the point of action.

(a)  

The hydrostatic pressure force exerted by a static fluid on a plane surface always acts

• Tangential to the surface

• Normal to the surface

• At any arbitrary angle

• Parallel to the base

For which plane surface is the centroidal depth (h̄) equal to the depth of centre of pressure (h*)?

• Inclined surface

• Vertical surface

• Horizontal surface

• Curved surface

The expression of hydrostatic force on an inclined surface is independent of

• Area

• Density

• Angle of inclination (θ)

• Depth

For the same fluid and area, which plane position gives the highest hydrostatic force?

• Fully horizontal

• Vertical

• Inclined at 45°

• All use the same expression; the magnitude varies via centroidal depth

The centre of pressure always lies

• Above the centroid

• At the centroid

• Below the centroid

• Coincident with free surface

For a triangular surface with its apex at the top and base at bottom, h* equals

• h/2

• 3h/4

• h/3

• 2h/3

For a semi-circular surface, the depth of centre of pressure below free surface is

• 3πD/32

• 5D/8

• 3D/4

• 3πD/16