Key Concepts in Physics

Gravitational Force:
- Attraction between masses.
- Weakest of the four forces.
Electromagnetic Force:
- Interaction between charged particles.
- Responsible for electricity and magnetism.
Strong Nuclear Force:
- Holds protons and neutrons together in the nucleus.
- Strongest force but acts over very short distances.
Weak Nuclear Force:
- Responsible for radioactive decay and neutrino interactions.
- Short-range force.

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

Kinetic Energy (KE):
- Energy of an object in motion; KE = 1/2 mv².
Potential Energy (PE):
- Energy stored in an object due to its position or state; PE = mgh (for gravitational).
Conservation of Energy:
- Energy cannot be created or destroyed, only transformed from one form to another.

First Law:
- Energy cannot be created or destroyed; ΔU = Q - W (Change in internal energy = heat added - work done).
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:
- Wavelength, frequency, amplitude, speed.
Types of Waves:
- Mechanical (require medium) and electromagnetic (do not require medium).
Sound Waves:
- Longitudinal waves that travel through compressions and rarefactions in a medium.

Ohm's Law:
- V = IR (Voltage = Current x Resistance).
Coulomb’s Law:
- The force between two charges is proportional to the product of the charges and inversely proportional to the square of the distance between them.
Magnetic Fields:
- Produced by moving electric charges and can exert forces on other moving charges.

Theory of Relativity:
- Special Relativity: Time dilation and length contraction occur at high speeds.
- General Relativity: Gravity is the curvature of spacetime caused by mass.
Quantum Mechanics:
- Describes the behavior of particles at the atomic and subatomic level.
- Key concepts include wave-particle duality, uncertainty principle, and quantization of energy.

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

Scientific Method:
- Observation, hypothesis, experimentation, analysis, conclusion.
Error and Uncertainty:
- Precision vs. accuracy; systematic vs. random errors.

These notes encompass essential principles and concepts within the field of physics, providing a structured overview for study and review.

Gravitational Force: Attraction between masses, the weakest force among the four fundamental forces.
Electromagnetic Force: Interaction between charged particles; essential for electricity and magnetism.
Strong Nuclear Force: Binds protons and neutrons in the atomic nucleus; the strongest force, effective only at very short ranges.
Weak Nuclear Force: Governs radioactive decay and neutrino interactions; short-range force.

First Law (Inertia): States that objects remain at rest or in uniform motion unless acted upon by an external force.
Second Law (F=ma): Defines force as the product of mass and acceleration, emphasizing the relationship between them.
Third Law (Action-Reaction): Asserts that every action has an equal and opposite reaction.

Kinetic Energy (KE): Energy associated with motion, calculated using the formula KE = 1/2 mv².
Potential Energy (PE): Energy stored due to position or state, commonly expressed as PE = mgh for gravitational potential energy.
Conservation of Energy: Principle stating that energy cannot be created or destroyed, only transformed or transferred.

First Law: Dictates energy conservation, expressed mathematically as ΔU = Q - W, where ΔU is the change in internal energy, Q is heat added, and W is work done.
Second Law: Indicates the natural tendency of systems to increase in entropy, implying that energy transformations are inherently inefficient.
Third Law: Describes the behavior of systems as temperature approaches absolute zero, suggesting that the entropy of a perfect crystal reaches zero.

Wave Properties: Key characteristics include wavelength, frequency, amplitude, and wave speed.
Types of Waves: Classification into mechanical waves, which require a medium, and electromagnetic waves, which do not.
Sound Waves: A type of longitudinal wave that propagates through compressions and rarefactions in a medium.

Ohm's Law: Relationship defining voltage as the product of current and resistance, expressed as V = IR.
Coulomb’s Law: Describes the electrostatic force between two charges; proportional to the product of their magnitudes and inversely proportional to the square of the distance between them.
Magnetic Fields: Generated by moving electric charges and capable of exerting forces on other moving charges.

Theory of Relativity: Comprises two parts; Special Relativity covers time dilation and length contraction with high velocities, while General Relativity describes gravity as spacetime curvature.
Quantum Mechanics: Explores the behavior of matter and energy at atomic and subatomic levels, introducing concepts like wave-particle duality and the uncertainty principle.

SI Units: Standard units used in physics include meter (m) for length, kilogram (kg) for mass, second (s) for time, Newton (N) for force, and Joule (J) for energy.

Scientific Method: A systematic approach involving observation, hypothesis formulation, experimentation, analysis, and conclusion.
Error and Uncertainty: Differentiates between precision (repeatability) and accuracy (closeness to true value) as well as systematic and random errors in measurements.