Key Concepts in Physics

Gravitational Force: Attraction between two masses; described by Newton's law of universal gravitation.
Electromagnetic Force: Interaction between charged particles; includes electric and magnetic forces.
Weak Nuclear Force: Responsible for radioactive decay and certain nuclear reactions.
Strong Nuclear Force: Holds protons and neutrons together in the nucleus.

Newton's Laws of Motion:
1. An object at rest stays at rest; an object in motion stays in motion unless acted upon.
2. F = ma (Force equals mass times acceleration).
3. For every action, there is an equal and opposite reaction.
Kinematics: Study of motion without considering forces; includes concepts like displacement, velocity, and acceleration.
Energy:
- Kinetic Energy: Energy of motion; KE = 1/2 mv².
- Potential Energy: Stored energy due to position; gravitational potential energy = mgh.

First Law: Energy cannot be created or destroyed, only transformed.
Second Law: Entropy of an isolated system always increases; energy transformations are not 100% efficient.
Third Law: As temperature approaches absolute zero, the entropy of a perfect crystal approaches zero.

Wave Properties: Amplitude, wavelength, frequency, speed.
Types of Waves:
- Mechanical Waves: Requires a medium (e.g., sound waves).
- Electromagnetic Waves: Does not require a medium (e.g., light waves).

Relativity:
- Special Relativity: Time and space are relative; mass-energy equivalence (E=mc²).
- General Relativity: Gravity is a curvature of spacetime caused by mass.
Quantum Mechanics: Describes the behavior of particles at atomic and subatomic levels.
- Wave-Particle Duality: Particles exhibit properties of both waves and particles.
- Uncertainty Principle: It is impossible to know both the position and momentum of a particle simultaneously.

Big Bang Theory: Origin of the universe; rapid expansion from a singularity.
Black Holes: Regions of spacetime with gravitational pull so strong that nothing can escape.

Kinematics: ( v = u + at ) (final velocity = initial velocity + acceleration x time).
Work: ( W = Fd \cos(\theta) ) (work = force x distance x cosine of the angle).
Momentum: ( p = mv ) (momentum = mass x velocity).

SI Units:
- Length: meter (m)
- Mass: kilogram (kg)
- Time: second (s)
- Force: newton (N)
- Energy: joule (J)

This summary provides a structured overview of key concepts within the field of physics, covering various branches and fundamental principles.

Gravitational Force: Attracts two masses; defined by Newton's law of universal gravitation, pivotal for understanding celestial mechanics.
Electromagnetic Force: Influences charged particles, encompassing both electric and magnetic interactions; essential for atomic structure and chemistry.
Weak Nuclear Force: Governs processes such as radioactive decay and certain nuclear interactions, crucial in nuclear physics.
Strong Nuclear Force: Binds protons and neutrons in the atomic nucleus, critical for nuclear stability.

Newton's Laws of Motion:
- An object in rest remains at rest; motion continues unless an external force is applied.
- Force is the product of mass and acceleration (F = ma).
- Actions have equal and opposite reactions, highlighting interactions between objects.
Kinematics: Analyzes motion parameters excluding force, focusing on displacement, velocity, and acceleration.
Energy Types:
- Kinetic Energy (KE): Calculated as ( KE = \frac{1}{2} mv^2 ), representing energy due to motion.
- Potential Energy: Energy stored due to an object's position, with gravitational potential energy given by ( PE = mgh ).

First Law: Energy conservation principle; energy is neither created nor destroyed but transformed.
Second Law: Total entropy in an isolated system increases over time, indicating irreversible processes and inefficiencies in energy conversion.
Third Law: At absolute zero, entropy of a perfect crystal approaches zero, indicating a state of perfect order.

Key Wave Properties: Amplitude, wavelength, frequency, speed are fundamental characteristics used to describe wave behavior.
Types of Waves:
- Mechanical Waves: Require a medium for propagation, such as sound waves.
- Electromagnetic Waves: Propagate without a medium, examples include light and radio waves.

Ohm's Law: Defines the relationship between voltage (V), current (I), and resistance (R) as ( V = IR ).
Circuit Elements: Basic components include resistors, capacitors, inductors, and power sources; essential in electrical engineering.
Magnetic Fields: Created by moving charges, these fields influence other charges in motion, foundational in electromagnetism.

Relativity:
- Special Relativity: Time and space are interconnected; mass-energy equivalence formulated as ( E=mc^2 ).
- General Relativity: Describes gravity as the curvature of spacetime, offering insights into large-scale cosmic phenomena.
Quantum Mechanics: Explores behaviors of particles at atomic and subatomic levels, revolutionizing our understanding of fundamental physics.
Wave-Particle Duality: Particles can behave as both waves and particles, a key concept in quantum theory.
Uncertainty Principle: Highlights that precise measurement of both position and momentum of a particle is unattainable simultaneously.

Big Bang Theory: Describes the universe's inception from a singularity, characterized by rapid expansion, influencing cosmic evolution.
Black Holes: Areas in spacetime with gravitational fields so intense that escape is impossible, important in stellar dynamics and general relativity.

Kinematic Equation: ( v = u + at ) (( v ): final velocity, ( u ): initial velocity, ( a ): acceleration, ( t ): time).
Work Equation: ( W = Fd \cos(\theta) ) (W: work, F: force, d: distance, θ: angle between force and direction of motion).
Momentum Formula: ( p = mv ) (p: momentum, m: mass, v: velocity).