Fluid Mechanics Quiz

What is the definition of a fluid in physics?

• A material that cannot change its shape

• A material that resists any shear force applied to it

• A material that continuously deforms under an applied shear stress

• A material that has a non-zero shear modulus

Answer explanation

A fluid is a material that continuously deforms under an applied shear stress.

What is the branch of physics concerned with the mechanics of fluids and the forces on them?

• Quantum Mechanics

• Fluid Mechanics

• Classical Mechanics

• Thermodynamics

Answer explanation

Fluid Mechanics is the branch of physics that studies the mechanics of fluids and the forces acting on them.

Why are fluids important in our lives?

• They affect every part of our lives

• All of the above

• They have shaped history and civilization

• They are essential for human survival

Answer explanation

Fluids are important because they affect every aspect of our lives, shape history and civilization, and are essential for human survival. All of the above choices are correct.

What is the unit of force in the SI system?

• Pound-force (lbf)

• Kilogram-force (kgf)

• Dyne (dyn)

• Newton (N)

Answer explanation

The unit of force in the SI system is the Newton (N).

What is the property of a fluid by virtue of which it offers resistance to shear?

• Surface tension

• Specific weight

• Viscosity

• Density

Answer explanation

Viscosity is the property of a fluid that offers resistance to shear. It determines the fluid's internal friction and flow behavior.

What is the dynamic viscosity of a fluid?

• The ratio of the dynamic viscosity over the density of the fluid

• The force required to accelerate a mass of 1 kg at a rate of 1 m/s^2

• The resistance of a fluid to deformation at a given rate

• The measure of a fluid's resistance to shear

Answer explanation

The dynamic viscosity of a fluid is the ratio of its dynamic viscosity to its density. It measures the fluid's resistance to shear.

What is the unit of viscosity in the cgs system?

• Pascal-second (Pa.s)

• Poise (P)

• Stoke (St)

• Newton-second per square meter (N.s/m^2)

Answer explanation

The unit of viscosity in the cgs system is the Stoke (St).

In which system of units is the force unit pound-force (lbf) used?

• English system

• Metric system

• SI system

• Imperial system

Answer explanation

The force unit pound-force (lbf) is used in the English system.

What is the dimension of viscosity in the cgs system?

• M L^-1 T^-2

• M L^-2 T^-1

• M^1 L^-1 T^-1

• M L^-1 T^-1

Answer explanation

Viscosity is the measure of a fluid's resistance to flow. In the cgs system, the dimension of viscosity is M L^-1 T^-1. This means it has units of mass per length per time, highlighting the correct choice.

How does viscosity generally change with temperature in liquids?

• It decreases with increasing temperature

• It increases with increasing temperature

• It remains constant with temperature

• It depends on the type of liquid

Answer explanation

Viscosity generally decreases with increasing temperature in liquids.