Introduction to Physics

• Physics is the study of matter, energy, and the interaction between them.

Branches of Physics

• Mechanics deals with the motion of objects, forces, and energy.
• Heat studies thermal energy, temperature, and heat transfer.
• Sound involves the study of sound waves and their properties.
• Optics explores light, its properties, and optical instruments.
• Electricity and Magnetism examines electric charges, electric currents, magnetic fields, and their interactions.
• Nuclear Physics investigates the structure, properties, and reactions of atomic nuclei.

Physical Quantities

• Physical quantities can be measured, consisting of numerical magnitude and a unit.
• Examples include length, mass, time, force, and energy.
• Base quantities are fundamental and independent, such as length, mass, time, electric current, temperature, luminous intensity, and amount of substance.
• Derived quantities are expressed using base quantities, examples are area, volume, speed and force.
• SI units (International System of Units) provide a standard for measurement.
• Length measurement uses meters (m).
• Mass measurement uses kilograms (kg).
• Time measurement uses seconds (s).
• Electric current measurement uses amperes (A).
• Temperature measurement uses kelvin (K).
• Luminous intensity measurement uses candelas (cd).
• Amount of substance measurement uses moles (mol).
• Scientific notation expresses numbers as a product of a number between 1 and 10 and a power of 10.
• Prefixes indicate multiples/submultiples of base units; kilo (k) for 10^3, milli (m) for 10^-3.

Kinematics

• Kinematics describes the motion of objects without considering the cause.
• Distance is the total length of the path.
• Displacement is the shortest distance between initial and final positions, including direction.
• Speed indicates how quickly an object covers distance.
• Velocity is the rate of change of displacement, including direction.
• Acceleration is the rate of change of velocity.
• Equations of motion relate displacement, initial velocity, final velocity, acceleration, and time for uniform acceleration.
• First equation of motion: v = u + at
• Second equation of motion: s = ut + (1/2)at^2
• Third equation of motion: 2as = v^2 - u^2
• Uniform circular motion occurs along a circular path at constant speed.

Dynamics

• Dynamics studies motion and the forces that cause it
• Force can alter an object's state of rest/motion.
• Newton's first law (inertia): objects remain at rest (or in uniform motion) unless acted upon by a force.
• Newton's second law: Force equals the rate of change of momentum, F = ma.
• Newton's third law: Every action has an equal, opposite reaction.
• Momentum is the product of mass and velocity, p = mv.
• The law of conservation of momentum states the total momentum in an isolated system remains constant.
• Friction opposes motion between surfaces.
• Types of friction include static, kinetic, and rolling friction.

Turning Effect of Forces

• Torque is the turning effect of a force, which is force multiplied by lever arm.
• Torque = Force × lever arm
• The centre of gravity is where an object's weight appears to act.
• A couple consists of equal, opposite forces creating rotation without translation.
• Equilibrium means net force and net torque on an object are zero.
• First condition of equilibrium: ΣF = 0 (net force is zero)
• Second condition of equilibrium: Στ = 0 (net torque is zero)

Gravitation

• Gravitation is the attractive force between objects with mass.
• Newton's law of universal gravitation: F = G(m1m2)/r^2; G is the gravitational constant.
• The acceleration due to gravity (g) is an object's acceleration from Earth's gravity.
• g ≈ 9.8 m/s^2
• Mass is the measure of matter in an object.
• Weight is the force of gravity on an object, W = mg.

Work and Energy

• Work occurs when force causes displacement, W = Fd cos θ.
• Energy is the ability to do work.
• Kinetic energy (KE) is the energy of motion, KE = (1/2)mv^2.
• Potential energy (PE) is stored energy.
• Gravitational potential energy: PE = mgh
• Power is the rate at which work is done, P = W/t.
• The law of conservation of energy states energy is neither created nor destroyed, only transformed.

Properties of Matter

• Matter exists as solid, liquid, and gas.
• Plasma is the fourth state of matter.
• Density is mass per unit volume, ρ = m/V.
• Pressure is force per unit area, P = F/A.
• Pascal's law states pressure applied to an enclosed fluid transmits equally throughout.
• Atmospheric pressure is the pressure of Earth's atmosphere.
• Archimedes' principle states buoyant force equals the weight of fluid displaced.
• Upthrust is the upward force of a fluid on an immersed object.

Thermal Properties of Matter

• Temperature measures hotness/coldness.
• Heat is thermal energy transfer due to temperature differences.
• Specific heat capacity is heat needed to raise 1 kg of a substance by 1 degree Celsius.
• Heat capacity is heat needed to raise an object's temperature by 1 degree Celsius.
• Latent heat is absorbed/released during state changes, without temperature change.
• Evaporation is the changing of a liquid into a gas.
• Condensation is the changing of a gas into a liquid.

Wave Motion and Sound

• Wave motion transfers energy through a medium by vibration.
• Transverse waves: particles vibrate perpendicular to wave direction.
• Longitudinal waves: particles vibrate parallel to wave direction.
• Wavelength is the distance between wave crests or troughs.
• Frequency is the number of waves per unit of time.
• The time period is the time for one complete wave to pass a point.
• Amplitude is the maximum particle displacement from equilibrium.
• Wave speed is v = fλ.
• Sound is a longitudinal wave from vibrating objects.
• Intensity of sound is the power per unit area.
• Loudness is the perception of sound intensity, which is affected by amplitude.
• Pitch is the perception of sound frequency.
• Ultrasound has frequencies above 20 kHz.

Light

• Reflection is the bouncing back of light from a surface.
• Laws of reflection: incident ray, reflected ray, and normal are coplanar; incidence angle equals reflection angle.
• Refraction is the bending of light when it passes from one medium to another.
• Snell's law: n1 sin θ1 = n2 sin θ2
• Total internal reflection occurs when light goes from denser to rarer medium at an angle greater than the critical angle.
• Lenses are curved transparent material that refract light.
• Convex lenses converge light.
• Concave lenses diverge light.

Optical Instruments

• A simple microscope uses a convex lens to magnify objects.
• A compound microscope uses two lenses (objective and eyepiece) for higher magnification.
• A telescope views distant objects.

Electrostatics

• Electric charge is a fundamental property.
• Positive and negative are the two types of electric charge.
• Like repel; opposites attract.
• Coulomb's law: Force is proportional to the product of charges, and inversely proportional to the square of the distance.
• The electric field is the region around a charge.
• Electric potential is electric potential energy per unit charge.
• A capacitor stores electric charge.
• Capacitance measures a capacitor's ability to store charge.

Current Electricity

• Electric current is the rate of electric charge flow.
• Ohm's law: Current is proportional to voltage, V = IR.
• Resistance opposes electric current flow.
• Series circuits: Components connect end-to-end, current is the same.
• Parallel circuits: Components connect side-by-side, voltage is the same.
• Electric power is the rate of converting electrical energy, P = VI.

Electromagnetism

• A magnetic field is the region around a magnet.
• Magnetic field lines show the field's direction.
• An electromagnet is a magnet created by electric current.
• Electromagnetic induction generates current by changing the magnetic field.
• Faraday's law: Induced voltage is proportional to the rate of change of magnetic flux.
• An electric generator converts mechanical energy into electrical energy.
• An electric motor converts electrical energy into mechanical energy.

Electronics

• Thermionic emission is the emission of electrons from a heated surface.
• A cathode-ray oscilloscope (CRO) displays electrical signals.
• Logic gates are electronic circuits performing logical operations.
• AND, OR, and NOT gates are basic logic gates.

Information and Communication Technology

• Information and Communication Technology (ICT) uses technology to process/communicate information.
• Hardware is the physical components of a computer.
• Software includes programs/data on a computer.
• Input devices enter data into a computer.
• Output devices display data from a computer.

Nuclear Physics

• Atomic number is the number of protons in an atom's nucleus.
• Mass number is the total of protons and neutrons in a nucleus.
• Isotopes are atoms of the same element with different neutron numbers.
• Radioactivity is the spontaneous emission of particles/energy.
• Alpha/beta particles, and gamma rays are emitted by radioactive substances.
• Half-life is the time for half the radioactive nuclei to decay.
• Nuclear fission is splitting a heavy nucleus into lighter ones, which releases energy.
• Nuclear fusion combines light nuclei into a heavier one and releases energy.