15 questions. Tap an option to check it instantly, then read the solution.
Practice SSC JE and state AE/JE civil engineering exam questions on Hydrostatic Pressure: total pressure force and centre of pressure on submerged vertical, horizontal, and inclined plane surfaces (rectangular gates, circular plates, triangular laminae), Pascal's law and its isotropic nature, the hydrostatic law (dp/dh = γ), hydrostatic paradox, liquid columns under vertical and horizontal rigid-body acceleration, and Archimedes' principle of buoyancy. Tap an option to check it, then open the complete step-by-step explanation with high-resolution engineering diagrams.
Question 1Easy
A tank has height and width as 4 m and 3 m, respectively. Determine the total water force, in kN, acting on the bottom of the tank when it is completely filled with water. Take density of water as 1000 kg/m³ and acceleration due to gravity as 9.81 m/sec² (Take the length of tank as 3 m.)
Absolute pressure is measured relative to absolute zero pressure (perfect vacuum): Absolute pressure = Gauge pressure + Atmospheric pressure.
Question 3Easy
In a barometer, air is trapped in the space labelled 'A' above the mercury level in the tube of the barometer, which measures 730 mmHg. If the atmospheric pressure is 750 mmHg, then the pressure of the trapped air is :
Atmospheric pressure supports both the mercury column and the trapped air pressure: P_air = P_atm − h_Hg = 750 − 730 = 20 mmHg.
Question 4Easy
An oil of mass density 800 kg/m³ is contained in a vessel. Calculate the height of water required to develop an equivalent hydrostatic pressure as that developed by oil of height 30 m. Take acceleration due to gravity as 9.81 m/sec²
Equating hydrostatic pressures: ρ_oil · g · h_oil = ρ_water · g · h_water ⇒ h_water = (800 × 30) / 1000 = 24 m.
Question 5Medium
Determine the total pressure on a circular plate of diameter 2 m, which is placed vertically in water in such a way that the Center of the plate is 2.5 m below the free surface of the water.
Total hydrostatic force P = ρ g A h̄ = 1000 × 9.81 × (π/4 × 2²) × 2.5 = 1000 × 9.81 × 3.1416 × 2.5 = 77,048 N.
Question 6Medium
A vertical gate closes a horizontal tunnel 4 m high and 3 m wide running full with water. The bottom of the vertical gate is located at a distance of 8 m from the free water surface. Determine the total fluid force (in kN) acting on the gate.
Top edge is at 8 − 4 = 4 m; centroid h̄ = 4 + 4/2 = 6 m. Force P = ρ g A h̄ = 1000 × 9.81 × (4 × 3) × 6 = 706.32 kN ≈ 706 kN.
Question 7Easy
Total pressure is a force exerted by a fluid when static mass of the fluid comes in contact with a plane or curved surface. The point of application of total pressure on the surface is known as ____.
The point on a submerged surface through which the resultant hydrostatic force acts is called the centre of pressure.
Question 8Easy
In an incompressible static fluid column, the rate of increase of pressure in the vertical direction is equal to weight density of fluid at that point. Which of the following is the law for this statements ?
Pascal's law states that fluid pressure at any point in a fluid at rest has the same magnitude in all directions: p_x = p_y = p_z.
Question 11Hard
An equilateral triangular plate of side a is immersed in water with one side at free water surface as in the given figure. The centre of pressure is below the water surface at a depth of :
Altitude h = a√3/2. For a triangle with base at the surface, h* = h/2 = (a√3/2)/2 = √3a/4.
Question 12Easy
The concept which defines 'the pressure at a certain horizontal level in a static fluid is proportional to the vertical distance to the surface of the fluid' is called
The Hydrostatic Paradox states that pressure at a given depth depends only on vertical distance to the free surface (p = ρgh), independent of the shape, volume, or total weight of liquid in the vessel.