Physics Chapter 10: Fluids

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What condition must be met for an object to float in a fluid?

The object's volume must be greater than the fluid's volume.

The object must be less dense than the fluid. (correct)

The object must be equal in weight to the fluid.

The object must be heavier than the fluid.

How is buoyant force defined according to Archimedes' principle?

The volume of fluid displaced divided by the object's density.

The weight of the object displaced.

The sum of gravitational and fluid pressure forces.

The upward force exerted by the fluid on the object. (correct)

Which statement is true regarding the flow of fluids?

The mass flow rate varies depending on the fluid's viscosity.

Laminar flow is characterized by high turbulence.

Turbulent flow has a consistent velocity throughout.

The equation of continuity states that mass in must equal mass out. (correct)

If a crown of mass 14.7 kg reads as 13.4 kg when submerged, what can be inferred about its density?

The crown is more dense than water. Signup and view all the answers

To generate lift for a load of 180 kg, what is the critical volume of helium needed?

300,000 cm3 Signup and view all the answers

Which of the following conditions is characteristic of turbulent flow?

Presence of eddies and chaotic changes. Signup and view all the answers

What net force acts on an object when it is submerged in a fluid and the buoyant force is greater than gravitational force?

Upward net force. Signup and view all the answers

What would happen to the submerged object if its density becomes higher than the fluid's density?

It would sink to the bottom. Signup and view all the answers

What does Bernoulli's equation indicate about fluid speed and pressure?

As fluid speed increases, pressure decreases. Signup and view all the answers

In the context of flow rates, what does the equation A1v1 = A2v2 imply about a fluid flowing through different diameter sections of a pipe?

Wider sections have slower flow speeds. Signup and view all the answers

Which principle explains the lift generated on an airplane wing?

Bernoulli’s principle Signup and view all the answers

What does a venturi meter measure in fluid dynamics?

Pressure differences Signup and view all the answers

According to Poiseuille's equation, which factor does NOT influence the rate of flow through a round tube?

Color of the fluid Signup and view all the answers

What is the relationship between tube radius and flow rate according to Poiseuille’s equation?

Flow rate is proportional to the third power of the radius. Signup and view all the answers

Under which condition is the density of a fluid considered constant?

When the fluid is a liquid and does not change phase Signup and view all the answers

Torricelli's theorem relates the speed of fluid flow from a spigot to which of the following?

The height of fluid above the spigot Signup and view all the answers

What is the relationship between density and specific gravity?

Specific gravity is the ratio of the density of a substance to the density of water. Signup and view all the answers

Which statement about pressure in a fluid is correct?

Pressure in a fluid is the same in all directions at a given depth. Signup and view all the answers

How is the specific gravity of a fluid calculated if a bottle mass is 89.22 g when filled with it?

It can be found by calculating the mass difference when filled with water. Signup and view all the answers

What is density defined as?

Mass per unit volume. Signup and view all the answers

If a 60-kg person stands on one foot, how would you determine the pressure exerted under that foot?

By calculating the weight and distributing it evenly across the area of the foot. Signup and view all the answers

In terms of fluid flow, what characteristic is unique to gases compared to liquids?

Gases can exert pressure on surrounding objects. Signup and view all the answers

What happens to pressure as depth increases in a fluid?

Pressure increases with depth because of the weight of the fluid above. Signup and view all the answers

What property of a solid defines its ability to maintain a definite shape?

Definite geometric structure. Signup and view all the answers

Study Notes

Chapter 10: Fluids

Fluids encompass liquids and gases, both capable of flowing.
Solids maintain a definite shape and volume.
Liquids have a fixed volume but adapt to container shapes.
Gases readily change shape and volume to fill their containers.

Density and Specific Gravity

Density (ρ) is mass per unit volume (ρ = m/V).
SI unit for density: kg/m³.
Density can also be expressed in g/cm³ .
To convert g/cm³ to kg/m³, multiply by 1000.
Water at 4°C has a density of 1 g/cm³ or 1000 kg/m³.
Specific gravity is the ratio of an object's density to water's density.

Pressure in Fluids

Pressure is force per unit area (Pressure = Force/Area).
SI unit for pressure: Pascal (Pa), where 1 Pa = 1 N/m².
Pressure in a fluid is the same in all directions at a given depth.
Pressure increases with depth in a liquid. Pressure = ρgh, where ρ is the density of the liquid, g is the acceleration due to gravity, and h is the depth.

Atmospheric Pressure and Gauge Pressure

Atmospheric pressure at sea level is approximately 1.013 × 10⁵ N/m².
Another pressure unit is the bar; 1 bar = 1.00 × 10⁵ N/m².
Gauge pressure is the difference between absolute pressure and atmospheric pressure.
Absolute pressure = Atmospheric pressure + Gauge pressure.

Pascal's Principle

If an external pressure is applied to a confined fluid, the pressure increases equally throughout the fluid.
Pascal's principle is used in hydraulic systems.

Measurement of Pressure

Open-tube manometers measure pressure differences relative to atmospheric pressure.
A mercury barometer is used to measure atmospheric pressure, with pressure often quoted in millimeters of mercury.

Buoyancy and Archimedes' Principle

Buoyant force is the upward force exerted by a fluid on a submerged object.
The buoyant force equals the weight of the fluid displaced by the object. F_B = ρ_fluidV_displacedg, where ρ_fluid is the fluid's density, V_displaced is the volume of fluid displaced, and g is the acceleration due to gravity.
An object floats if the buoyant force equals the object's weight.
The fraction of an object submerged in a fluid is related to the densities of the object and the fluid.

Fluids in Motion

Laminar flow is smooth, streamlined flow.
Turbulent flow is characterized by eddies and greater viscosity.
The mass flow rate is constant at different points in a horizontal pipe (as long as no fluid is added or removed). ρ₁A₁v₁ = ρ₂A₂v₂, where ρ is density, A is the cross-sectional area, and v is the fluid speed.

Bernoulli's Equation

Bernoulli's equation describes relationships between pressure, fluid speed, and height in a flowing fluid.
P₁ + ½ρv₁² + ρgy₁ = P₂ + ½ρv₂² + ρgy₂, where P is pressure, ρ is fluid density, v is fluid speed, and y is height.

Applications of Bernoulli's Principle

Bernoulli's principle explains lift on airplane wings and other phenomena.
A venturi meter measures fluid flow by observing pressure differences.

Flow in Tubes and Poiseuille's Equation

The rate of flow in a tube depends on fluid viscosity, pressure difference, and tube radius. The rate of flow (Q) is given by Poiseuille's equation
Q =πR⁴(P₁-P₂)/8ηL, where R is radius, P₁ and P₂ are pressures, η is viscosity, and L is length .

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the fascinating world of fluids in this quiz, covering the properties of liquids and gases, density, specific gravity, and pressure principles. Test your understanding of these key concepts in fluid mechanics and their applications in real-world scenarios.