Physics Formulas and Concepts Summary
Moments of Inertia
I = m * d². System for discrete masses: I = Σmᵢ * dᵢ². System for continuous bodies: I = ∫ (d² * dm). Steiner’s Theorem (Parallel Axis Theorem): Ia = Ib + m * d² (where Ib is the moment of inertia about an axis passing through the center of mass G, and the axis ‘a’ is parallel to ‘b’ at a distance ‘d’).
Kinematics of a Point
Position
Defined by a path-time law.
Path (Trajectory)
The set of positions of point P. Can be the intersection of two surfaces. Eliminate time ‘t’ from
Read MoreWireless Signals, Radio & Network Protocols Explained
Antennas and Electromagnetic Waves
In many communication systems, it’s not necessary for the sender and receiver to be connected by a physical cable. This wireless communication is achieved using an antenna. Antennas are devices responsible for converting electromagnetic waves into electrical impulses (reception) and vice versa (transmission).
An electrical conductor, such as an antenna, can emit energy as electromagnetic waves if a variable electric current flows through it. These electromagnetic
Read MoreCore Physics: Quantities, Motion, and Forces
Physical Quantities
Physical quantities are properties of matter that can be measured.
Scalar Quantities
These are defined only by a number and the corresponding unit. Examples include temperature (T), mass (m), length, and pressure.
Vector Quantities
To define these, besides the number and the unit, it is necessary to add the direction and sense they possess. Examples include velocity, acceleration, force, and momentum.
Elements of a Vector
- Module: The numerical value of the magnitude.
- Direction: The line
Fundamentals of Electricity Concepts
Historical Figures in Electricity
Joseph Thomson
Inventor of the mass spectrometer, discovered the electron and isotopes.
Thales
Observed electrical phenomena by rubbing amber with a cloth and noted that the bar attracted objects.
Otto von Guericke
Observed that repulsion occurred between electrified bodies after they had been attracted. He devised the first electrostatic generator, a sulfur ball, and produced sparks, which led him to speculate about the electrical nature of lightning.
Pieter van Musschenbroek
Performed
Read MorePhysics Concepts: Motion, Vectors, and Scalars
Vector-Scalar product: The product of a scalar with a vector only changes the magnitude of the vector, but does not mess with direction: n(A) = nA
Dot product (Scalar product): This kind of product between two vectors is also called scalar product because its result is a number that means a scalar quantity. It is defined as: A. B = |A||B| cos θ
Cross product (Vector product): This kind of product between two vectors is also called scalar product because its result is a vector quantity. It is defined
Read MoreScientific Revolutions: Copernicus, Newton, Einstein
What is a Scientific Theory?
A scientific theory is a set of ideas or hypotheses (assumptions) that satisfies two conditions: it must align with observations or recorded data, and it must not contradict fundamental concepts.
The Copernican Revolution: Sun-Centered Universe
For about 2,000 years, from the time of Aristotle until after Columbus’s voyages to the New World, it was believed that the Earth was the center of the universe (the geocentric theory). The shift to the Copernican heliocentric theory,
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