Classical Mechanics Overview

Classical Mechanics

• Classical mechanics describes the motion of macroscopic objects, from planets to cars.
• It's based on 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 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.
• Concepts: Force, mass, acceleration, momentum, energy, work, power, torque, rotation, angular momentum, simple harmonic motion, conservation laws (momentum, energy).
• Applications: Calculating trajectories, predicting the motion of objects, designing machines, analyzing planetary orbits.
• Limitations: Classical mechanics breaks down at very high speeds (approaching the speed of light) and at very small scales (atomic and subatomic levels).

Thermodynamics

• Thermodynamics deals with heat, temperature, and energy.
• Zeroth Law: If two systems are each in thermal equilibrium with a third system, the two systems are in thermal equilibrium with each other.
• First Law: Energy can be transferred and transformed, but it cannot be created or destroyed. (ΔU = Q - W) where ΔU is change in internal energy, Q is heat, and W is work.
• Second Law: The total entropy of an isolated system can only increase over time. Often expressed in terms of heat engines, refrigerators, and other devices. There are several equivalent statements of the second law.
• Third Law: The entropy of a perfect crystal at absolute zero is zero.
• Concepts: Temperature, heat, work, internal energy, enthalpy, entropy, heat engines, refrigerators, phases of matter, thermodynamic cycles.
• Applications: Designing power plants, understanding climate change, developing new materials, analyzing chemical reactions.

Electromagnetism

• Electromagnetism describes the interactions between electric and magnetic fields.
• Electric Fields: Created by electric charges. Force on a charge is proportional to the strength of the field and the charge.
• Magnetic Fields: Created by moving electric charges (currents). Forces between magnetic poles (north and south). Moving charges experience forces in magnetic fields.
• Maxwell's Equations: A set of four equations that describe the behavior of electric and magnetic fields.
• Concepts: Electric charge, electric field, electric potential, magnetic field, magnetic flux, electromagnetic induction, electromagnetic waves, light, optics.
• Applications: Generating electricity, designing motors, building communication systems, understanding light and optics.

Modern Physics

• Modern physics builds upon classical physics but explores phenomena at extreme scales and speeds.
• Relativity: Einstein's theory of relativity encompasses special relativity (constancy of the speed of light, time dilation, length contraction) and general relativity (gravity as the curvature of spacetime).
• Quantum Mechanics: Describes the behavior of matter at the atomic and subatomic level. Quantized properties, wave-particle duality, uncertainty principle.
• Concepts: Special relativity, general relativity, quantum mechanics, atomic structure, nuclear physics, particle physics, the standard model of particle physics.
• Applications: Developing nuclear power, designing atomic clocks, understanding the universe (cosmology).

Atomic and Nuclear Physics

• Atomic physics investigates the structure and behavior of atoms.
• Nuclear physics studies the structure and behavior of atomic nuclei.
• Key atomic concepts include energy levels, electron transitions, spectra, atomic orbitals, and the Bohr model, plus more modern models.
• Key nuclear physics concepts include isotopes, radioactivity, nuclear reactions, fission, fusion, and nuclear stability.
• Applications: Medical imaging (e.g., MRI, PET), radiation therapy, nuclear power, materials science.