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

LASER = Light Amplification by Stimulated Emission of Radiation

A laser is actually an oscillator rather than a simple amplifier. The difference is that an oscillator has positive feedback in addition to the amplifier.

Light is understood in a general sense: electromagnetic radiation with a wavelength around 1 μm. Thus, one can have infrared, visible, or ultraviolet lasers.

The atomic medium with population inversion used in the laser is called the active medium. The positive optical feedback is obtained by placing the active medium between two mirrors. One of them (M1) totally reflects back the light (R1 = 1) to the active medium, while the other one (M2, called the output coupler) has a reflectivity less than unity (R2 < 1) and allows some... Continue reading "Introduction to LASER Technology: Types, Operation, and Applications" »

Henry Cavendish

conducted an experiment that determined the value of the constant...

Rev of Heavenly Spheres

Axis of Rotation

Tycho Brahe

Gravitational Force

Centripetal Force

Uniform Circular Motion

Inertial Mass

Centrifugal Force

Apparent Weightlessness

DEFINITIONS

DISTANCE

How much ground an object has covered/traveled.

DISPLACEMENT

The change in position of an object.

SCALAR QUANTITY

Quantity that only has magnitude and no direction.

VECTOR

Physical quantity that has both magnitude and direction.

CONSTANT SPEED

Speed that does not change.

VELOCITY

Speed in a given direction.

FRAME OF REFERENCE

A background used to judge motion/speed (precise location of an object).

INSTANTANEOUS SPEED

Speed at a given moment.

ENERGY

The capacity/power to do work/move an object by applying force.

MATTER

Anything that has mass and takes up space (how much matter).

WEIGHT

Measure of how gravity pulls matter.

SPEED

Amount of distance traveled in a certain amount of time.

AVERAGE SPEED

Total distance divided by total time.

TIME DISTANCE

Human Evolution: From *Orrorin* to *Homo Sapiens*

The Earth was formed 4,500 million years ago. There is evidence that the hominid family emerged 6 million years ago, with our species, Homo sapiens sapiens, appearing only 150,000 years ago. Our species is characterized by the development of the brain, which allows for complex social behavior, consciousness of our own existence, and a great capacity for communication. The evolution of our species includes the following:

Key Hominid Species

1. Orrorin tugenensis: Lived more than 6 million years ago (MA). They were omnivorous, lived in jungles, measured 1.4 meters, were bipedal, and were descendants of the current chimpanzees, but with differences in the pelvis, humerus, and femur.
2. Ardipithecus ramidus:

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" »

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

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" »

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" »

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" »