Key Concepts in Physics

Gravitational Force
- Attraction between masses.
- Governs planetary motion.
Electromagnetic Force
- Acts between charged particles.
- Responsible for electricity and magnetism.
Weak Nuclear Force
- Responsible for radioactive decay.
- Plays a role in nuclear reactions.
Strong Nuclear Force
- Holds protons and neutrons together in the nucleus.
- Overcomes electromagnetic repulsion between protons.

Newton's First Law (Inertia)
- An object at rest stays at rest; an object in motion stays in motion unless acted upon by a net force.
Newton's Second Law (F=ma)
- The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.
Newton's Third Law (Action-Reaction)
- For every action, there is an equal and opposite reaction.

Work (W)
- Defined as ( W = F \cdot d \cdot \cos(\theta) ) (force applied over a distance).
Kinetic Energy (KE)
- Energy of motion: ( KE = \frac{1}{2}mv^2 ).
Potential Energy (PE)
- Energy stored due to position: ( PE = mgh ) (mass × gravity × height).
Conservation of Energy
- Energy cannot be created or destroyed, only transformed.

Wave Properties
- Wavelength, frequency, amplitude, speed.
Types of Waves
- Transverse (e.g., light) and longitudinal (e.g., sound).
Sound
- Travels as a longitudinal wave through media.
- Speed depends on medium (faster in solids than in gases).

Zeroth Law
- If two systems are in thermal equilibrium with a third, they are in equilibrium with each other.
First Law (Conservation of Energy)
- Energy cannot be created or destroyed; it only changes forms.
Second Law
- Entropy of an isolated system always increases; processes occur in the direction of increasing entropy.
Third Law
- As temperature approaches absolute zero, the entropy of a perfect crystal approaches zero.

Electric Fields
- Area around a charged particle where a force would be exerted on other charges.
Magnetic Fields
- Created by moving charges; affects other moving charges.
Faraday's Law of Induction
- A changing magnetic field induces an electromotive force (EMF) in a closed loop.

Relativity
- Special Relativity: Time and space are relative; speed of light is constant.
- General Relativity: Gravity is the curvature of spacetime.
Quantum Mechanics
- Describes behavior of particles at atomic and subatomic levels.
- Concepts include wave-particle duality, uncertainty principle, and quantization of energy levels.

SI Units
- Length: meter (m)
- Mass: kilogram (kg)
- Time: second (s)
- Force: Newton (N)
- Energy: Joule (J)
Dimensional Analysis
- Technique for converting units and solving problems in physics.

Engineering and Technology
- Principles of physics are applied in designing structures, electronics, and machinery.
Medical Physics
- Use of physics concepts in medical imaging and radiation therapy.
Astrophysics
- Study of celestial bodies and phenomena using physical principles.

Gravitational Force: Attraction that governs planetary motion and affects the orbits of celestial bodies.
Electromagnetic Force: Interaction between charged particles, responsible for the phenomena of electricity and magnetism.
Weak Nuclear Force: Responsible for processes like radioactive decay and plays a key role in nuclear reactions.
Strong Nuclear Force: Essential for holding protons and neutrons together within the atomic nucleus, overcoming repulsive forces among protons.

Newton's First Law: An object remains at rest or in uniform motion unless acted upon by an external net force, highlighting the concept of inertia.
Newton's Second Law: The acceleration (a) of an object is directly proportional to the net force (F) acting on it and inversely proportional to its mass (m), formulated as ( F = ma ).
Newton's Third Law: Every action has an equal and opposite reaction, indicating the interaction between forces.

Work (W) is defined as the product of force (F), distance (d), and the cosine of the angle ((\theta)) between them: ( W = F \cdot d \cdot \cos(\theta) ).
Kinetic Energy (KE): The energy associated with motion, calculated with the formula ( KE = \frac{1}{2}mv^2 ) where m is mass and v is velocity.
Potential Energy (PE): Energy stored due to an object's position, given by ( PE = mgh ), where g is gravitational acceleration and h is height.
Conservation of Energy: Energy cannot be created or destroyed; it can only change from one form to another.

Wave Properties: Key characteristics include wavelength, frequency, amplitude, and speed, which define wave behavior.
Types of Waves: Includes transverse waves (like light) and longitudinal waves (like sound).
Sound Propagation: Travels as longitudinal waves through various media, with speed varying according to the medium, generally faster in solids compared to gases.

Zeroth Law of Thermodynamics: Establishes a way to define thermal equilibrium, stating that if two systems are each in equilibrium with a third, they are in equilibrium with one another.
First Law of Thermodynamics: Reflects the principle of conservation of energy, indicating that energy transformations occur but cannot be created or destroyed.
Second Law of Thermodynamics: States that entropy in an isolated system tends to increase over time, dictating the direction of spontaneous processes.
Third Law of Thermodynamics: As temperature approaches absolute zero, the entropy of a perfect crystal approaches zero.

Electric Fields: Region around a charged particle where it exerts forces on other charged particles.
Magnetic Fields: Generated by moving charges, these fields influence the behavior of other moving charges nearby.
Faraday's Law of Induction: Indicates that a changing magnetic field within a closed circuit induces an electromotive force (EMF).

Relativity:
- Special Relativity defines the interdependence of space and time, with the speed of light as a universal constant.
- General Relativity explains gravity as the curvature of spacetime.
Quantum Mechanics: Describes atomic and subatomic particle behavior, introducing concepts like wave-particle duality, the uncertainty principle, and quantized energy levels.

SI Units:
- Length: meter (m)
- Mass: kilogram (kg)
- Time: second (s)
- Force: Newton (N)
- Energy: Joule (J)
Dimensional Analysis: Method for converting units and solving physics-related problems, ensuring consistent dimensionality.

Engineering and Technology: Physics principles are critical to designing and constructing structures, electronics, and various machinery.
Medical Physics: Application of physics concepts in medical imaging technologies and cancer treatment methods like radiation therapy.
Astrophysics: Investigates celestial objects and cosmic phenomena using principles grounded in physics.