Physics: Classical Mechanics and Core Concepts

• Physics is a natural science concerning the study of matter, its constituents, motion, and behavior through space and time, alongside energy and force study.
• A primary goal of physics is understanding the behavior of the universe and it is a fundamental scientific discipline

Core Concepts

• Classical mechanics studies macroscopic object motion at speeds far below light speed.
• Thermodynamics studies heat, work, energy, and their relationships.
• Electromagnetism studies forces between electrically charged particles.
• Optics studies light behavior and properties, its interactions with matter, and the creation of instruments using or detecting it.
• Quantum mechanics studies matter and energy behavior at atomic/subatomic levels.
• Relativity (special and general) describes the relationship between space, time, gravity, and object motion at high speeds or in strong gravitational fields.

Classical Mechanics

• Describes the motion of macroscopic objects.
• Key concepts are displacement, velocity, acceleration, force, mass, and energy.
• Newton's laws of motion are foundational.
  • First law: Objects at rest stay at rest; objects in motion stay in motion unless acted upon by force.
  • Second law: Force equals the rate of momentum change; for constant mass, force equals mass times acceleration (F = ma).
  • Third law: Every action has an equal and opposite reaction.
• Conservation laws (e.g., energy, momentum) are central.

Thermodynamics

• Studies the relationships between heat, work, and energy.
• Deals with bulk properties of matter and energy transfer on a macroscopic scale.
• Key concepts are temperature, heat, internal energy, entropy, and enthalpy.
• Laws of thermodynamics:
  • Zeroth law: Systems in thermal equilibrium with a third system are in equilibrium with each other.
  • First law: Energy is conserved; internal energy change equals heat added minus work done.
  • Second law: The entropy of an isolated system increases over time.
  • Third law: As temperature approaches absolute zero, entropy approaches a minimum or zero.

Electromagnetism

• Describes the interaction between electric charges and magnetic moments.
• Maxwell's equations govern it, describing how electric and magnetic fields are generated and altered by each other, charges, and currents.
• Key concepts are electric charge, electric field, magnetic field, electric current, voltage, and electromagnetic waves.
• Electromagnetic waves propagate at light speed, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

Optics

• Studies light behavior and properties.
• Covers reflection, refraction, diffraction, interference, and polarization of light.
• Geometric optics treats light as rays and designs lenses/optical instruments.
• Wave optics explains phenomena like interference and diffraction, dealing with the wave nature of light.

Quantum Mechanics

• Describes matter and energy behavior at atomic/subatomic levels.
• Central concepts are energy quantization, wave-particle duality, the uncertainty principle, and quantum entanglement.
• Schrödinger's equation is fundamental, detailing how a physical system's quantum state changes.
• Applications include understanding atomic structure, chemical bonding, and semiconductor behavior.

Relativity

• Special relativity relates space and time for observers in relative motion at constant velocity.
  • Postulates include the constancy of light speed in all inertial frames and the principle of relativity.
  • Consequences are time dilation, length contraction, and mass increase with velocity.
  • Mass-energy equivalence is E=mc², where E is energy, m is mass, and c is the speed of light.
• General relativity describes gravity as spacetime curvature caused by mass and energy.
  • Predicts gravitational time dilation, gravitational lensing, and black holes.
  • It describes the evolution of the universe and objects in strong gravitational fields.

Measurement and Units

• Physics relies on precise measurements of physical quantities.
• The International System of Units (SI) is the standard system.
• Base SI units:
  • Meter (m) for length
  • Kilogram (kg) for mass
  • Second (s) for time
  • Ampere (A) for electric current
  • Kelvin (K) for thermodynamic temperature
  • Mole (mol) for the amount of substance
  • Candela (cd) for luminous intensity
• Derived units combine base units (e.g., Newton (N) for force, Joule (J) for energy).
• Very large or small numbers use scientific notation for concise expression.

Problem Solving in Physics

• Understand the problem: Identify knowns, unknowns, and relevant principles.
• Draw a diagram: Visuals clarify the problem and relationships.
• Choose a strategy: Select appropriate equations or principles.
• Solve the equations: Calculate unknown quantities.
• Check the answer: Verify if reasonable, has correct units, and answers the question.

Branches of Physics

• Astrophysics: The physics of the cosmos, including stars, galaxies, and the universe as a whole.
• Biophysics: Applies physics to study biological systems.
• Chemical Physics: Studies physical phenomena and processes underlying chemical systems.
• Geophysics: The physics of Earth, including atmosphere, oceans, and interior.
• Nuclear Physics: Studies the structure, properties, and reactions of atomic nuclei.
• Particle Physics: Studies fundamental matter constituents and governing forces.
• Condensed Matter Physics: Studies physical properties of condensed phases of matter.

An overview of physics, focusing on the study of matter, energy, and their interactions. Key areas include classical mechanics, thermodynamics, electromagnetism, and optics. It also touches on quantum mechanics and relativity.