1. Basic Concepts
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Physics is the study of matter, energy, and motion.
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Matter has mass and occupies space.
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Mass is the quantity of matter in a body.
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Weight is the force of gravity acting on mass.
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Density equals mass divided by volume.
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Specific gravity is the ratio of substance density to water.
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Force equals mass multiplied by acceleration.
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The unit of force is the Newton (N).
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One Newton equals one kilogram-meter per second squared.
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Pressure equals force divided by area.
2. Motion and Laws
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Displacement is the shortest distance between two points.
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Speed is the rate of change of distance.
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Velocity is speed in a given direction.
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Acceleration is the rate of change of velocity.
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Deceleration is negative acceleration or slowing down.
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Newton’s first law states a body remains at rest or constant motion unless acted by force.
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Newton’s second law defines force equals mass times acceleration.
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Newton’s third law states every action has equal and opposite reaction.
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Momentum equals mass times velocity.
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Impulse equals force multiplied by time.
3. Work, Energy, and Power
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Work is done when a force moves an object.
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Work equals force multiplied by distance moved.
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Unit of work is joule (J).
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Energy is the capacity to do work.
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Kinetic energy equals half mass times velocity squared.
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Potential energy equals mass times gravity times height.
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Mechanical energy equals potential plus kinetic energy.
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Power equals work done divided by time.
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Unit of power is watt (W).
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One horsepower equals 746 watts approximately.
4. Machines and Efficiency
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Simple machines change magnitude or direction of force.
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Levers have three classes depending on fulcrum, effort, and load.
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Mechanical advantage equals load divided by effort.
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Velocity ratio equals distance moved by effort to load.
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Efficiency equals mechanical advantage divided by velocity ratio.
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Pulley systems provide mechanical advantage by rope arrangements.
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Inclined plane reduces effort needed to lift weight.
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Gear trains transfer motion and torque between shafts.
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Screw jack converts rotary motion into linear motion.
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No machine is 100% efficient due to friction losses.
5. Properties of Matter
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Elasticity is the ability of material to return to original shape.
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Hooke’s law states stress is proportional to strain within elastic limit.
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Stress equals force divided by cross-sectional area.
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Strain equals change in length divided by original length.
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Modulus of elasticity equals stress divided by strain.
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Plastic deformation is permanent change beyond elastic limit.
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Ductility allows a material to be drawn into wire.
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Malleability allows a material to be hammered into sheets.
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Brittleness is property of breaking without deformation.
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Toughness is resistance to fracture when energy is absorbed.
6. Fluids – Statics
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Fluid includes both liquids and gases.
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Pascal’s law states pressure applied to fluid is transmitted equally.
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Hydrostatic pressure equals density times gravity times height.
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Archimedes’ principle states a body immersed in fluid experiences buoyant force equal to weight of displaced fluid.
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Buoyant force acts upward against gravity.
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Specific weight equals weight per unit volume.
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Gauge pressure is measured above atmospheric pressure.
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Absolute pressure equals gauge pressure plus atmospheric pressure.
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Manometer is used to measure fluid pressure difference.
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Barometer measures atmospheric pressure using mercury column.
7. Fluids – Dynamics
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Bernoulli’s principle states increase in fluid speed decreases pressure.
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Continuity equation states area times velocity remains constant in streamline flow.
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Laminar flow has smooth parallel layers with no mixing.
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Turbulent flow contains irregular eddies and mixing motion.
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Viscosity is internal friction between fluid layers.
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Reynolds number determines type of fluid flow.
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Cavitation occurs when vapor bubbles form and collapse in liquid.
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Flow rate equals volume of fluid per unit time.
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Venturi tube measures fluid velocity using pressure difference.
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Pitot tube measures total and static pressures in airflow.
8. Heat and Temperature
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Heat is energy transferred due to temperature difference.
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Temperature measures average kinetic energy of particles.
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Celsius scale has freezing point 0°C and boiling point 100°C.
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Kelvin scale absolute zero equals −273°C.
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Heat flows from hot to cold bodies.
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Specific heat capacity is heat required to raise unit mass by one degree.
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Latent heat is energy absorbed or released during phase change.
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Conduction transfers heat through solids by particle vibration.
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Convection transfers heat through fluids by movement of molecules.
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Radiation transfers heat without any medium.
9. Gas Laws
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Boyle’s law: pressure inversely proportional to volume at constant temperature.
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Charles’s law: volume directly proportional to temperature at constant pressure.
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Gay-Lussac’s law: pressure directly proportional to temperature at constant volume.
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Combined gas law relates pressure, volume, and temperature.
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Ideal gas law: PV = nRT.
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Absolute zero is temperature where molecular motion stops.
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Isothermal process occurs at constant temperature.
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Adiabatic process occurs without heat transfer.
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Gas expands when heated and contracts when cooled.
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Standard atmospheric pressure equals 1013.25 hPa or 14.7 psi.
10. Sound and Light
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Sound requires a medium for transmission.
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Frequency is number of vibrations per second measured in hertz.
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Speed of sound increases with temperature.
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Ultrasound has frequency above 20,000 hertz.
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Reflection occurs when sound or light bounces from surface.
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Refraction is bending of light when passing between mediums.
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Diffraction is spreading of waves around obstacles.
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Interference occurs when two waves overlap each other.
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Light travels in straight lines in uniform medium.
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White light is a mixture of seven visible colors.