Nature of Matter and Chemical Compounds

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Questions and Answers

What happens to pressure as the speed of a moving fluid increases?

Pressure decreases (correct)

Pressure fluctuates unpredictably

Pressure increases

Pressure remains constant

What is the Venturi Effect associated with?

Decreased temperature in fluids

Increased pressure in fluids

Increased viscosity of fluids

Reduction of static pressure through a constriction (correct)

How does lift generate for an aircraft wing according to Bernoulli's theorem?

By increasing pressure on the top surface

By equalizing air pressure above and below the wing

By decreasing velocity of air over the upper surface

By creating a pressure difference between the upper and lower wing surfaces (correct)

What does the law of conservation of energy state regarding thermal energy?

Thermal energy can be transformed into other forms, but not created or destroyed Signup and view all the answers

What process requires physical contact for heat transfer?

Conduction Signup and view all the answers

Which of the following describes convection?

Transfer of heat by bulk movement of fluid Signup and view all the answers

Which unit is commercially used to quantify heat energy?

Calorie Signup and view all the answers

What is the SI unit for all forms of energy?

Joule Signup and view all the answers

What is required for forces to be used to perform work?

Energy must be available Signup and view all the answers

What describes a system in which the resultant of all forces is zero?

It is in a state of equilibrium Signup and view all the answers

Which lever is classified as a first-class lever?

Crowbar Signup and view all the answers

What is the formula for calculating Mechanical Advantage (MA)?

MA = Load/Effort Signup and view all the answers

What type of stress does tension resist?

A pulling force Signup and view all the answers

Under which condition does strain return to normal?

When it is less than the elastic limit Signup and view all the answers

Which type of stress occurs when external forces distort a body causing adjacent layers to slide?

Shear Signup and view all the answers

What is known as the balance point of an aircraft?

Centre of gravity (CG) Signup and view all the answers

What is inertia defined as?

The property of a mass to resist changes in its state of motion Signup and view all the answers

How is work calculated when a force is applied to move an object?

W = F x S Signup and view all the answers

Which of the following describes kinetic energy?

Energy possessed due to motion Signup and view all the answers

What is the SI unit of power?

Watt Signup and view all the answers

What does the law of conservation of energy state?

The total energy of an isolated system remains constant Signup and view all the answers

If a car converts chemical energy from petrol, what type of energy does it produce?

Mechanical energy, heat, and sound Signup and view all the answers

Which of the following statements is true about potential energy?

It is energy stored due to an object's position or condition Signup and view all the answers

What happens to potential energy when an object is released from a height?

It converts into kinetic energy Signup and view all the answers

Study Notes

Nature of Matter

Matter occupies space and has mass, existing in solid, liquid, and gaseous states
Elements are the simplest form of matter, composed of atoms
Atoms consist of protons (positive charge), neutrons (neutral charge), and electrons (negative charge) arranged around a dense nucleus
Electrons orbit in shells, each with a maximum number (2n²), where n is the shell number
Ions are atoms that have gained or lost electrons to form a positive or negative charge
Isotopes are atoms of the same element with different numbers of neutrons

Chemical Compounds

109 known elements form most matter through compounds
Compounds comprise identical molecules with specific proportions of different atoms
Chemical bonds form when atoms link, often by transferring electrons between molecules
Mixtures are composed of two or more substances with their own characteristics

States of Matter

Solids have a definite shape and volume, independent of container
Liquids have a definite volume, taking the shape of their container
Gases have no fixed shape or volume, filling their container

Topic 2: Statics

Force: A force can accelerate bodies, start, stop, or change their motion
Equilibrium: When the net force on an object is zero, it is in equilibrium at rest or uniform motion
Levers: Simple machines that act as a force multiplier

Topic 2: Forces, Moments and Couples

Force is a push or pull that can change a body's motion
Moments and couples cause rotation
Forces are represented as vectors

Elements of Theory of Stress, Strain and Elasticity

Stress: Force per unit area causing deformation
Strain: Deformation of material due to stress
Elastic limit: Point where material returns to normal shape
Hooke's Law: Strain is directly proportional to stress below elastic limit
Tension: Resistance to pulling force
Compression: Resistance to crushing force
Shear: Adjacent layers slide past
Torsion: Resistance to twisting

Aircraft Riveting

Uses compressive forces

Pressure and Buoyancy

Pressure in a fluid depends on height, gravity, and fluid density.
Density is mass per unit volume
Specific gravity compares densities to water, i.e. weight of material against water weight
Buoyancy force equals weight of displaced fluid (Archimedes' principle)
- An object floats if it displaces more fluid than its weight
- Gasoline has a specific gravity of 0.72 meaning equal volume weighs 72% as much as water

Topic 2.2 Kinetics

Displacement- difference between initial and final position
Distance- total path taken
Speed- rate of change of distance
Velocity- speed with direction
Acceleration - change in velocity

Topic 2.3 Dynamics

Inertia is a property that resists changes in motion
Newton's first law: An object stays at rest or in uniform motion unless acted upon by a net force
Work: Force x distance (measured in Joules)
Power: Rate of doing work (measured in Watts)

Periodic Motion

Repeated motion, like oscillations or vibrations
The energy is wave energy in periodic motion

Heat Transfer

Conduction: Heat transfer through direct contact
Convection: Heat transfer through fluid movement
Heating water in a kettle, heating air in a house, atmospheric heat circulation are examples of convection.
Calorie (cal): measures heat for raising the temperature of one gram of water by one degree Celsius.
British thermal unit (Btu): measures heat for raising the temperature of one pound of water by one degree Fahrenheit.

### Thermal Energy and Latent Heat

Latent heat: The amount of heat absorbed or released during a change of state without a change in temperature
Latent heat of vaporization / evaporation: Amount of heat required to boil a liquid or turn it to gas
Latent heat of fusion: Amount of heat required to melt a solid to liquid
Sensible heat: The heat required that causes a change in temperature

Topic 2.4 Fluid Dynamics

Liquids are generally incompressible
Viscosity: Resistance of fluid flow (thick oil is more viscous than thin oil)
Viscosity Index: How much viscosity changes with a temperature change (in lubricating oils, this helps the oil not change viscosity in a wide range of operating temps)
Coanda Effect: Fluid tends to stick to curved surfaces (e.g., air around a curved wing)
Boundary Layer: Region of reduced speed in fluid flow (crucial for airflow around objects)

Topic 3: Thermodynamics

Energy conservation: Energy cannot be created nor destroyed, only transformed
Thermal energy is energy related to heat, and it can be transformed into mechanical energy and viceversa
- Thermal energy refers to heat (e.g., heat from combustion in an engine)
- Kinetic energy is energy a body has because of its motion (e.g., expanding gases in a turbine)

Topic 4: Optics (Light)

Visible light is electromagnetic radiation
Speed of light is 3 x 10⁸ m/s in a vacuum
Reflected light: Light bounces off a surface at the same angle it hit the surface
Refracted light: Light bends when it passes through different materials.
Refractive index (n) is a value that describes how much a substance slows light
Dispersion: Spreading of light into different colours

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Description

This quiz explores the fundamental concepts of matter, including its states, atomic structure, and chemical compounds. You will learn about the roles of protons, neutrons, and electrons, as well as how atoms form bonds to create various substances. Test your understanding of the nature and behavior of matter along with its classification.