Physics

Fluid Mechanics

637 Questions

Fluid mechanics is a core physics topic that evaluates the principles of liquid pressure, buoyancy, density, and viscosity through complex numerical problems. The questions require calculating the volume of submerged objects, understanding hydraulic jumps, and applying fundamental fluid statics principles. It is a highly scoring subject for candidates preparing for technical and engineering competitive exams.

Liquid pressure and depthBuoyancy and densityVolume expansionHydraulic jump calculationsSurface tension mechanics

Fluid Mechanics Questions

Multiple choice

What is the cavitation number?

  1. The ratio of the NPSH to the dynamic head of the pump

  2. The ratio of the vapor pressure of the liquid to the dynamic head of the pump

  3. The ratio of the NPSH to the static head of the pump

  4. The ratio of the vapor pressure of the liquid to the static head of the pump
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The cavitation number is the ratio of the NPSH to the dynamic head of the pump. It is a dimensionless number that is used to predict the likelihood of cavitation in a pump.

Multiple choice

What is the effect of fluid elasticity on cavitation?

  1. Increasing the fluid elasticity increases the likelihood of cavitation

  2. Increasing the fluid elasticity decreases the likelihood of cavitation

  3. Fluid elasticity has no effect on cavitation

  4. The effect of fluid elasticity on cavitation is not well-defined
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Increasing the fluid elasticity decreases the likelihood of cavitation because it makes it more difficult for vapor bubbles to grow and collapse. Elastic fluids have the ability to store energy, which can be used to absorb the energy of the collapsing vapor bubbles. This reduces the damage caused by cavitation and makes it less likely to occur.

Multiple choice

Which fluid property is important in determining the buoyancy of an object?

  1. Density

  2. Viscosity

  3. Surface Tension

  4. Compressibility
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Density is the key fluid property that determines the buoyancy of an object. Buoyancy is the upward force exerted by a fluid on an object immersed in it.

Multiple choice

The compressibility of a fluid is inversely proportional to:

  1. Density

  2. Viscosity

  3. Surface Tension

  4. Bulk Modulus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Compressibility is the reciprocal of the bulk modulus. Therefore, it is inversely proportional to the bulk modulus.

Multiple choice

The equation that describes the relationship between pressure, density, and height in a fluid is known as:

  1. Bernoulli's equation

  2. Pascal's law

  3. Archimedes' principle

  4. Poiseuille's equation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pascal's law states that pressure applied to a fluid in a closed container is transmitted equally to every point in the fluid.

Multiple choice

What is the relationship between density and pressure in seawater?

  1. As pressure increases, density increases.

  2. As pressure increases, density decreases.

  3. Pressure has no effect on density.

  4. Density is independent of pressure.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

As pressure increases in seawater, its density also increases. This is because the increased pressure forces the water molecules closer together, resulting in a higher mass per unit volume.

Multiple choice

What is the relationship between surface tension and the formation of bubbles?

  1. Surface tension promotes bubble formation.

  2. Surface tension inhibits bubble formation.

  3. Surface tension has no effect on bubble formation.

  4. The relationship depends on the liquid's properties.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Surface tension acts against the expansion of bubbles, making it more difficult for them to form and persist.