Notes, summaries, assignments, exams, and problems for Physics

Michelangelo's David is a monumental sculpture depicting the biblical King David. Rendered in a classical style, he is completely nude and portrayed as an athlete, carrying a sling in his left hand (resting on his shoulder) and a stone in his right. Facial features are clearly visible, along with curly hair, defined musculature, and a pronounced contrapposto.

Symbolic Analysis of David

Michelangelo depicted King David not merely as a young athlete, but as a man in the prime of his life. The artist chose as the subject of the work the moment prior to the confrontation between David and Goliath, unlike other representations where Goliath's defeated head often appears at his feet. Therefore, the figure displays a contained and expectant gaze, imbuing... Continue reading "Michelangelo's David: Form, Symbolism, and Florentine Identity" »

Aristotle's Cosmic Conception

Aristotle, in the fourth century BC, distinguished two regions of the universe:

The Terrestrial Region (Below)

• Earth occupies the center of the universe.
• All terrestrial bodies are formed by combining four elements: earth, water, air, and fire.
• Earth is the heaviest element and tends downwards, while fire tends upwards.

The Celestial Region (Above)

• It consists of transparent, concentric spheres surrounding the Earth.
• In each sphere, one of the heavenly bodies (Sun, Moon, Venus, etc.) is located.
• The outermost sphere contains the fixed stars.

Ptolemy's Geocentric System

Developed by Ptolemy (2nd Century AD), this system placed Earth at the center of the universe and described the movements of celestial bodies using Earth as... Continue reading "Evolution of Astronomical Models: From Ancient Cosmos to Newton" »

Early Greek Conceptions: The Ionian School

Some Greek thinkers made the first attempts to conceive the world as the result of natural processes, rather than an incomprehensible work of the gods. This was notably the case for the philosophers of the Ionian school, which flourished around the 6th century BC.

According to their views, the universe was initially in a state of primordial unity, where everything was mixed. From this unity, pairs of opposites arose, interacting with each other. These interactions led to the formation of heavenly bodies on one hand, and the Earth with its plants and animals on the other.

The Ionian philosophers conceived the Earth as a flat disk floating in the center of the celestial sphere.

The Spherical Earth: Pythagoras

Deriving Key Physics Formulas

Deriving v = u + at

    → v = u + at

Deriving s = ut + ½ at²

V_average =     But v = u + at       → V_average =  

V_average = s/t    → s = V_average(t)    → s = (t)     → s = ut + ½ at²

Deriving v² = u² + 2as

v = u + at   → v² = u² + 2uat + (at)²    {multiply out both sides}

We can rewrite this as v² = u² + 2a(ut + ½ at²)             {because 2a(ut + ½ at²) = 2uat + (at)²}

Now sub in s = ut + ½ at²    → v² = u² + 2as

Force and Motion

- F = Bqv: Consider a section of conductor of length l through which a current I is flowing.

If q is the charge which carries the current in this section of the conductor, then:

I = q/t, where t is the time it takes the charge q to travel

The Dawn of Technology: From Necessity to Innovation

The earliest tools emerged from necessity, improving hunting and defense for humans and animals. The first technological revolution for our species involved carved stone, marking the beginning of human ingenuity.

Economic Transformations Through Technology

• Predatory Food Economy: Early human societies relied on hunting and gathering.
• Agricultural-Livestock Economy: The Neolithic period saw the shift to sedentary agricultural and livestock activities, a profound change driven by new tools and techniques.

The Metal Revolutions

The discovery and mastery of metals ushered in new eras, allowing for the creation of more advanced tools and weapons:

• Copper Age
• Bronze Age
• Iron Age

These metal revolutions enabled... Continue reading "Technological Progress: From Stone Tools to Atomic Clocks" »

In the Beginning

Certain questions about our existence on Earth are so fundamental that they have been incorporated into religious mythologies. These questions not only concern the origin of the Earth and the evolution of life but also extend to the origin of the universe and to the nature of space and time. Did the universe have a beginning, and will it ever end? What existed before the universe formed? Does the universe have limits, and what exists beyond those limits? It is proper to raise these questions at the beginning of a geochemistry course because they are within the scope of cosmochemistry.

The Big Bang

The universe started like a bubble in a stream. At first, it was not there, and suddenly it formed and expanded rapidly as though it... Continue reading "Cosmochemistry: Unveiling the Universe's Origin and Evolution" »

Sound: Concepts and Characteristics

In physics, sound is defined as a periodic perturbation in air. It is a mechanical longitudinal wave, where the motion of particles in the medium travels in the same direction as the wave, which propagates through an elastic medium. This periodic perturbation originates sound waves.

For sound to be produced, there must be vibrating matter and an elastic medium. For example, a guitar's vibrating strings produce sound.

Speed of Sound

The speed of sound (v) is calculated depending on the medium of propagation. In air, its speed is 331 m/s at 0°C and 1 atm. To estimate the speed of sound in air at different temperatures, the following formula is used:

Where temperature is measured in °C.

Speed of Sound in Various

2.1 Thermodynamics: Concepts

Thermodynamics is a science that studies energy and its transformations.
A thermodynamic property is a system’s characteristic that does not depend on history. There are two types of thermodynamic properties: intensive and extensive properties. The intensive property is independent of the mass or size of the system (e.g., temperature, pressure, and density), whereas an extensive property is dependent (e.g., mass, weight, volume, and total energy).

A system is in thermal equilibrium when the temperature is uniform.
2.2 Zeroth Law of Thermodynamics

If two bodies are in thermal equilibrium with a third one, then all three are in thermal equilibrium with each other.

Remember that thermal equilibrium occurs when the temperature... Continue reading "Understanding Thermodynamics and Wave Motion Concepts" »

Understanding Structures: Definition and Types

A structure is the set of elements intended to resist the forces acting upon it, providing rigidity and maintaining its shape.

Examples of Structures

Natural Structures

• Trees
• Bones
• Spiderwebs

Artificial Structures

• Buildings
• Bridges
• Furniture

Types of Artificial Structures

Framework Structures

These structures form the skeletal framework of an object, providing its primary support and shape.

Laminar or Plate Structures

These structures surround and protect an object, typically composed of thin sheets of metal, plastic, or similar materials.

Forces and Stresses on Structures

Key Concepts: Force, Load, and Stress

Defining Force

A force is any influence that can deform a body (a static effect) or alter its state of motion... Continue reading "Structural Engineering Fundamentals: Forces, Stresses, and Design Principles" »

Analysis of "On Home Beaches" by Les Murray

Body Image in a Consumerist Society

Les Murray's poem "On Home Beaches" explores the theme of body image and its significance in a consumerist society. It highlights the humiliation faced by individuals who do not conform to conventional beauty standards, particularly in environments like beaches where bodies are exposed.

Subverting the Sonnet Form

The poem adopts the sonnet form, traditionally associated with love and tenderness. Murray ironically subverts this form by using it to depict mortification and ridicule, contrasting the conventional themes of love with the harsh realities of body shaming.

Imagery of the Seaside

The poem utilizes vivid imagery of the seaside, including sand, towels, waves, foam,... Continue reading "Body Image and the Outback in Australian Poetry: Analysis of Les Murray and Henry Lawson" »