Understanding Force, Weight, and Motion: A Physics Primer
Understanding Force, Weight, and Motion
Force is anything that can deform a body or change its state of rest or motion.
Force = mass × acceleration
Representation of Forces
Forces are represented by arrows. The line segments indicate the direction, and the pointed end of an arrow indicates the sense.
Types of Forces
- Instantaneous forces: Act only during a very short period (e.g., kicking a ball).
- Constant forces: Act on an ongoing basis (e.g., the Earth’s gravity).
The unit of force is the Newton (N) in
Read MoreThe Scientific Revolution: Astronomy, Method, and Physics
Factors Favoring the Scientific Revolution
- Adoption of Arabic numerals over Roman numerals.
- Invention of the printing press (around the 1450s).
- Secularization of scientific methodology and the rise of the new bourgeoisie.
- Great sea voyages, which spurred advancements in shipbuilding and navigation tools (e.g., sails, compasses).
- Humanist interest in crafts and agriculture.
- Improved calculations for directing cannon fire.
- Fusion of science and technique (e.g., telescope, microscope).
New Astronomy
Nicolaus
Read MoreUnderstanding Vectors, Motion, and Newton’s Laws
Scalar Product
The scalar product of two vectors, a and b, results in a scalar value, k. This is obtained by multiplying the magnitudes of the two vectors and the cosine of the angle between them. The formula is expressed as:
k = |a| |b| cos(α)
For the vectors to be perpendicular, their scalar product must be zero. The formula can be rearranged to solve for the cosine of the angle:
cos(α) = (a · b) / (|a| |b|)
Vector Product
The vector product of two vectors, a and b, results in a new vector with the
Read MoreRelativity: Space, Time, Mass-Energy, and Quantum Effects
Relativity: Concepts and Postulates
The study of relativity establishes that time and space are relative; this means that they cannot be described using an absolute reference system because the measurement of space and time depends on the observer.
Einstein’s Special Theory of Relativity
In 1905, Albert Einstein published the Special Theory of Relativity, based on two postulates:
Postulates of Special Relativity
- Postulate 1: The laws of physics are the same for all reference frames moving at a constant
Understanding the Universe: Theories, Evolution, and Components
Origin of the Universe
Big Bang Theory:
Proposed by Lemaître (1927) and developed by Gamow (1948). All matter, space, and energy were initially concentrated at a single point (cosmic egg). A consequence of the instability was the large initial explosion and the beginning of the expansion of the universe. As the universe cooled gradually, elementary particles connected via electromagnetic and nuclear forces to form atoms. Thus came matter, space, and time. As the universe expanded and cooled, the
Read MoreUnderstanding Energy: Concepts, Types, and Conservation
World War
WWII is the best of all
bullets are bullets, well
assignatura: history
dica em adam
The Concept of Energy in Physics
In physics, the universal law of conservation of energy, which is the basis for the first law of thermodynamics, indicates that the energy attached to an isolated system remains constant over time. However, the theory of special relativity establishes an equivalence between mass and energy by which all bodies, by virtue of being formed of matter, contain energy. Moreover, additional
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