Mechanical Properties of Fluids quiz

The SI unit of surface tension is:

Hydraulic brakes work on:

Bernoulli's principle is based on the conservation of:

The terminal velocity of a small sphere in a viscous liquid is proportional to:

The capillary rise of a liquid in a tube is:

The pressure at the bottom of a liquid column depends on:

The SI unit of the coefficient of viscosity is:

Detergents help in cleaning because they:

The excess pressure inside a soap bubble of radius r is:

According to the equation of continuity, when a pipe narrows, the speed of the fluid:

Explain the term gauge pressure. (2 marks)

Why does a dam have a broader base than top? (2 marks)

What is streamline flow? (2 marks)

Explain why a spinning ball curves in the air using Bernoulli's principle. (2 marks)

Why does water come out faster when the opening of a hose is partly closed? Use the equation of continuity. (2 marks)

What is terminal velocity? (2 marks)

Define surface energy and relate it to surface tension. (2 marks)

Why do insects walk on the surface of water? (2 marks)

Explain why hot oil spreads more easily than cold oil. (2 marks)

State Torricelli's law. (2 marks)

A copper ball of radius 2.0 mm falls through oil at a terminal velocity of 6.5 cm/s. Find the viscosity of the oil. Densities of oil and copper are 1.5 x 10^3 and 8.9 x 10^3 kg/m^3. (3 marks)

Find the work done in blowing a soap bubble of radius 1 cm. Take the surface tension of soap solution as 0.03 N/m. (3 marks)

The air speeds above and below an aeroplane wing are 70 m/s and 63 m/s. Find the pressure difference and the lift on a wing of area 40 m^2. Take the density of air as 1.3 kg/m^3. (3 marks)

Find the absolute pressure at a depth of 10 m in a lake. (3 marks)

Find the terminal velocity of a water droplet of radius 10^-5 m falling in air of viscosity 1.8 x 10^-5 Pa s, neglecting the density of air. (3 marks)

Read the passage and answer the questions. A water tank on the roof of a building has its water surface 15 m above a tap on the ground floor. (i) Find the gauge pressure at the tap. (ii) Find the speed of water from the open tap. (iii) Why do upper floors get lower water pressure? (5 marks)

Read the passage and answer the questions. A garden hose of cross-section 2 cm^2 carries water at 1.5 m/s. It ends in a nozzle of 0.5 cm^2. (i) Find the speed at the nozzle. (ii) Find the volume of water flowing per second. (iii) Which principle is used? (5 marks)

Read the passage and answer the questions. A car service station uses a hydraulic lift. The small piston has area 5 cm^2 and the large piston has area 500 cm^2. A car of mass 1000 kg is to be lifted. (i) Find the weight of the car. (ii) Find the force needed on the small piston. (iii) State the principle used. (5 marks)

Read the passage and answer the questions. A student drops steel balls of different sizes into a tall jar of glycerine. (i) Which ball reaches the bottom first? (ii) What forces act on a ball moving at terminal velocity? (iii) How does the terminal velocity change if the radius doubles? (5 marks)

Read the passage and answer the questions. A thin glass capillary tube is dipped in water and another in mercury. (i) In which does the liquid rise? (ii) In which is the liquid level depressed? (iii) How does the rise of water change if the tube radius is halved? (5 marks)

Derive the expression for pressure at a depth h in a liquid. Explain the hydrostatic paradox and the working of a mercury barometer. (6 marks)

State Pascal's law and explain the working of a hydraulic lift and hydraulic brakes. (6 marks)

Derive the equation of continuity and state Bernoulli's principle. Explain its applications in Torricelli's law and dynamic lift. (6 marks)

Explain viscosity and Stokes' law. Show how terminal velocity is reached by a body falling through a fluid. (6 marks)

Explain surface tension and surface energy. Derive the excess pressure inside a liquid drop and inside a soap bubble. (6 marks)