Physics: Understanding Mechanics

• Physics is a natural science that studies matter, its fundamental constituents, motion, and behavior through space and time, and related entities of energy and force.

Mechanics

• Mechanics is the branch of physics concerned with the motion of bodies under the action of forces, including the special case in which a body remains at rest.
• Classical mechanics describes the motion of macroscopic objects, from projectiles to parts of machinery, and astronomical objects, such as spacecraft, planets, stars, and galaxies.
• It provides extremely accurate results as long as the objects being examined are large enough to be measured and move at speeds much smaller than the speed of light.
• Classical mechanics is based on Isaac Newton's laws of motion.
• Key concepts in classical mechanics include displacement, velocity, acceleration, mass, force, momentum, energy, and work.
• Newton's First Law states that 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 states that the force acting on an object is equal to the mass of that object times its acceleration (F = ma).
• Newton's Third Law states that for every action, there is an equal and opposite reaction.
• Work is defined as the force applied to an object times the distance over which it is applied (W = Fd).
• Energy is the ability to do work. Kinetic energy is the energy of motion (KE = 1/2 mv^2), and potential energy is stored energy.
• The law of conservation of energy states that energy cannot be created or destroyed, but it can be transferred from one form to another.
• Momentum is the product of an object's mass and its velocity (p = mv).
• The law of conservation of momentum states that the total momentum of a closed system remains constant if no external forces act on it.
• Rotational motion involves objects moving in a circular path around an axis.
• Torque is a twisting force that causes rotation.
• Angular momentum is a measure of an object's rotation.
• Simple harmonic motion is a type of periodic motion where the restoring force is proportional to the displacement.

Thermodynamics

• Thermodynamics is the branch of physics that deals with heat, work, and energy, and the relationships between them.
• It describes how thermal energy is converted to and from other forms of energy and how it affects matter.
• The four laws of thermodynamics govern the behavior of energy and matter.
• The zeroth law of thermodynamics states that if two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.
• The first law of thermodynamics states that energy is conserved. 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).
• The second law of thermodynamics states that the entropy of an isolated system always increases or remains constant. It introduces the concept of irreversibility.
• The third law of thermodynamics states that the entropy of a system approaches a minimum value as the temperature approaches absolute zero.
• Temperature is a measure of the average kinetic energy of the particles in a system.
• Heat is the transfer of energy between objects or systems due to a temperature difference.
• Work is the energy transferred when a force causes a displacement.
• Entropy is a measure of the disorder or randomness of a system.
• Enthalpy is a thermodynamic property of a system, defined as the sum of the internal energy and the product of pressure and volume (H = U + PV).
• Specific heat is the amount of heat required to raise the temperature of one unit mass of a substance by one degree Celsius.
• Phase transitions involve changes in the physical state of a substance, such as melting, boiling, and sublimation.
• Heat engines convert thermal energy into mechanical work.
• Refrigerators and heat pumps transfer heat from a cold reservoir to a hot reservoir, requiring work input.
• The Carnot cycle is a theoretical thermodynamic cycle that provides the maximum possible efficiency for a heat engine operating between two temperatures.

Electromagnetism

• Electromagnetism is the branch of physics that deals with the interactions between electric charges and magnetic fields.
• It encompasses a wide range of phenomena, including electric circuits, radio waves, and light.
• Electric charge is a fundamental property of matter that can be positive or negative.
• Coulomb's law describes the force between two electric charges. The force is proportional to the product of the charges and inversely proportional to the square of the distance between them.
• Electric field is the force per unit charge exerted on a test charge at a given point.
• Electric potential is the potential energy per unit charge at a given point.
• Electric current is the rate of flow of electric charge.
• Resistance is the opposition to the flow of electric current.
• Ohm's law states that the voltage across a conductor is proportional to the current flowing through it (V = IR).
• Capacitance is the ability of a system to store electric charge.
• Magnetic field is a field of force created by moving electric charges.
• Magnetic force is the force exerted on a moving charge by a magnetic field.
• Faraday's law of induction states that a changing magnetic field induces an electromotive force (EMF).
• Inductance is the property of a circuit that opposes changes in current.
• Maxwell's equations are a set of four equations that describe the behavior of electric and magnetic fields.
• Electromagnetic waves are disturbances that propagate through space as a result of the interaction between electric and magnetic fields.
• Light is an electromagnetic wave.
• The electromagnetic spectrum includes radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

Quantum Physics

• Quantum physics is the branch of physics that deals with the behavior of matter and energy at the atomic and subatomic levels.
• It is characterized by the quantization of energy, momentum, and other physical quantities.
• Quantum mechanics provides a probabilistic description of nature.
• Wave-particle duality states that particles can exhibit wave-like properties and waves can exhibit particle-like properties.
• The Heisenberg uncertainty principle states that it is impossible to know both the position and momentum of a particle with perfect accuracy.
• Quantum entanglement is a phenomenon in which two or more particles become linked together in such a way that the state of one particle instantly affects the state of the other, regardless of the distance between them.
• The Schrödinger equation is a mathematical equation that describes the time evolution of a quantum system.
• The quantum model of the atom describes the electrons in an atom as existing in discrete energy levels or orbitals.
• Quantum field theory combines quantum mechanics with special relativity and describes particles as excitations of quantum fields.
• Standard Model of particle physics describes all known fundamental forces and particles