Question

What will be the hydrostatic pressure exerted by water moving with constant velocity at a depth of 10 m from the surface? Given ρ =1000 kg/m³ 
1. 981 kN/m²
2. 49 kN/m²
3. Pressure will depend on magnitude of velocity
4. 98 kN/m²

Answer 1

Correct Answer - Option 4 : 98 kN/m²

CONCEPT:

• The normal force exerted by liquid at rest on a given surface in contact with it is called the thrust of liquid on that surface.
• The normal force (or thrust) exerted by liquid at rest or liquid moving with constant velocity per unit area of the surface in contact with it, is called pressure of liquid or hydrostatic pressure.
• If Po is the atmospheric pressure then for a point at depth h below the surface of a liquid of density ρ,
• Hydrostatic pressure P is given by

P = Po + ρgh

Calculation:

Given:

h = 10 m, ρ =1000 kg/m3 ,  Po = Atmospheric gauge pressure = 0

P = Po + ρgh = 0 + 1000 × 9.81 × 10 = 98 kN/m2