Fundamentals of Physics

• Physics is a natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force.
• Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.

Core Concepts

• Classical mechanics describes the motion of macroscopic objects, from projectiles to parts of machinery, and astronomical objects, such as spacecraft, planets, stars, and galaxies.
• Thermodynamics deals with heat, work, and energy, and the relationships between them. It defines macroscopic variables, such as temperature, entropy, and pressure, that describe average properties of material bodies.
• Electromagnetism studies the interactions of electrically charged particles with electric and magnetic fields.
• Quantum mechanics deals with the behavior of matter and energy at the atomic and subatomic levels. It introduces concepts such as quantization of energy, wave-particle duality, and the uncertainty principle.
• Relativity, including special relativity and general relativity, describes the structure of spacetime and gravity. Special relativity deals with the relationship between space and time for objects moving at constant speeds, while general relativity describes gravity as the curvature of spacetime caused by mass and energy.

Core Principles

• Conservation of Energy: The total energy of an isolated system remains constant. Energy can be transformed from one form to another but cannot be created or destroyed.
• Conservation of Momentum: In a closed system, the total momentum remains constant if no external forces act on it.
• Conservation of Angular Momentum: The total angular momentum of a closed system remains constant in the absence of external torque.
• Conservation of Electric Charge: The net electric charge of an isolated system remains constant. Charge can be transferred from one object to another, but the total charge remains the same.

Mechanics

• Kinematics describes the motion of objects without considering the causes of motion. Key concepts include displacement, velocity, acceleration, and time.
• Dynamics studies the causes of motion, relating force and mass to acceleration through Newton's laws of motion.
• Newton's First Law (Law of Inertia): An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by a force.
• Newton's Second Law: The force acting on an object is equal to the mass of that object times its acceleration (F = ma).
• Newton's Third Law: For every action, there is an equal and opposite reaction.
• Work is the energy transferred to or from an object by means of a force acting on the object. It is calculated as the force times the displacement in the direction of the force (W = Fd cosθ).
• Energy exists in various forms, including kinetic energy (energy of motion), potential energy (stored energy), thermal energy, and electromagnetic energy.

Thermodynamics

• Zeroth Law of Thermodynamics: If two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.
• First Law of Thermodynamics: The change in internal energy of a system is equal to the heat added to the system minus the work done by the system (ΔU = Q - W).
• Second Law of Thermodynamics: The entropy of an isolated system tends to increase over time. This law introduces the concept of irreversibility in natural processes.
• Third Law of Thermodynamics: As the temperature approaches absolute zero, the entropy of a system approaches a minimum or zero value.
• Heat transfer occurs through conduction, convection, and radiation. Conduction involves the transfer of heat through a material by direct contact. Convection involves the transfer of heat by the movement of fluids. Radiation involves the transfer of heat by electromagnetic waves.

Electromagnetism

• Electric charge is a fundamental property of matter that can be positive or negative. Like charges repel, and opposite charges attract.
• Coulomb's Law describes the force between two point charges. The force is proportional to the product of the charges and inversely proportional to the square of the distance between them.
• Electric Field: The electric field is a vector field that describes the force exerted on a positive test charge at any point in space.
• Magnetism is produced by moving electric charges. Magnetic fields exert forces on moving charges and magnetic materials.
• Electromagnetic Induction: A changing magnetic field induces an electromotive force (EMF) in a conductor. This is the principle behind electric generators and transformers.
• Maxwell's Equations: A set of four equations that describe the behavior of electric and magnetic fields, and their interactions with matter.
• Electromagnetic waves, such as light, are disturbances in electric and magnetic fields that propagate through space. They include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

Quantum Mechanics

• Quantum mechanics describes the behavior of matter and energy at the atomic and subatomic level.
• Wave-Particle Duality: Particles can exhibit both wave-like and particle-like properties. For example, electrons can behave as both particles and waves.
• Uncertainty Principle: There is a fundamental limit to the precision with which certain pairs of physical properties of a particle, such as position and momentum, can be known simultaneously.
• Quantum Entanglement: A quantum mechanical phenomenon in which the quantum states of two or more objects are linked together, even when the objects are separated by a large distance.
• Quantum Superposition: A quantum mechanical principle that states that a quantum system can exist in multiple states simultaneously until it is measured.

Relativity

• Special Relativity: Describes the relationship between space and time for objects moving at constant speeds in inertial frames of reference. Key concepts include time dilation, length contraction, and the equivalence of mass and energy (E=mc²).
• General Relativity: Describes gravity as the curvature of spacetime caused by mass and energy. Massive objects warp the spacetime around them, causing other objects to move along curved paths.
• Gravitational waves are disturbances in the curvature of spacetime, generated by accelerating massive objects.

Optics

• Reflection occurs when light bounces off a surface. The angle of incidence is equal to the angle of reflection.
• Refraction occurs when light passes from one medium to another and changes direction due to a change in speed.
• Lenses are used to focus or disperse light. Convex lenses converge light rays, while concave lenses diverge light rays.
• Diffraction is the bending of waves around obstacles or through narrow openings.
• Interference occurs when two or more waves overlap to produce a resultant wave of greater or lower amplitude.

Physics is a natural science that studies matter, energy, and their interactions. It explores the fundamental constituents, motion, and behavior of the universe. Core concepts include classical mechanics, thermodynamics, electromagnetism and quantum mechanics.