Classical Mechanics Overview

Classical Mechanics

• Classical mechanics describes the motion of macroscopic objects, from planets to cars.
• It relies on Newton's laws of motion and gravitation to model the interactions and movements of objects.
• Key concepts include: force, mass, acceleration, momentum, energy, and conservation laws.
• Newton's first law (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 an unbalanced force.
• Newton's second law: the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. (F=ma).
• Newton's third law: for every action, there is an equal and opposite reaction.
• Applications of classical mechanics include calculating trajectories, analyzing collisions, and predicting the behaviour of mechanical systems.
• Classical mechanics can accurately describe phenomena at everyday scales, but fails to account for objects moving at near-light speeds or at the atomic level.

Thermodynamics

• Thermodynamics deals with the relationships between heat, work, and energy in a system.
• It focuses on the macroscopic properties of systems, such as temperature, pressure, and volume, rather than the microscopic behaviour of molecules.
• Key concepts include: temperature, heat, work, internal energy, and the laws of thermodynamics.
• Zeroth law: if two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.
• First law: energy cannot be created or destroyed, only transferred or changed from one form to another. (ΔU = Q - W).
• Second law: the total entropy of an isolated system can only increase over time. Clausius formulation states that heat cannot spontaneously flow from a colder object to a hotter object. Kelvin-Planck formulation states that it is impossible to devise a cyclically operating device that solely converts heat completely into work.
• Third law: the entropy of a perfect crystal approaches zero as the temperature approaches absolute zero.
• Applications include designing engines, refrigerators, and other thermal devices.

Electromagnetism

• Electromagnetism describes the interactions between electric charges and magnetic fields.
• It encompasses a wide range of phenomena, from static electricity to electromagnetic waves.
• Key concepts include: electric charge, electric field, magnetic field, electric potential, and electromagnetic waves.
• Coulomb's Law: the force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.
• Gauss's Law: the net electric flux through any closed surface is proportional to the enclosed electric charge.
• Faraday's Law of Induction: a changing magnetic field induces an electromotive force (EMF) in a conductor.
• Ampere's Law: a current produces a magnetic field.
• Applications include generating electricity, designing motors, and building communication systems.

Optics

• Optics deals with the behaviour of light, including its reflection, refraction, diffraction, and interference.
• Light can be treated as a wave or a particle, depending on the context.
• Key concepts include: reflection, refraction, lenses, mirrors, diffraction, interference, and polarization.
• Snell's Law: describes how light bends when it passes from one medium to another.
• Principles of lenses and mirrors: used to focus and manipulate light rays, creating images.
• Applications include designing telescopes, microscopes, and eyeglasses.

Modern Physics

• Modern physics extends classical physics to describe phenomena at microscopic scales and high speeds.
• Key concepts include: quantum mechanics, special relativity, and general relativity.
• Quantum mechanics describes the behaviour of matter and energy at the atomic and subatomic level, including wave-particle duality and quantization of energy.
• Special relativity describes the relationship between space and time, and the behaviour of objects moving at near-light speeds, including the relationship of time and space, and the constancy of the speed of light in a vacuum .
• General relativity describes gravity as a curvature of spacetime caused by mass and energy.
• Applications of modern physics are pervasive and include technologies like lasers, semiconductors, and nuclear power.