Celestial Mechanics: Kepler’s Laws, Tides, and the Expanding Universe
Celestial Mechanics: Kepler’s Laws
Johannes Kepler, a German astronomer and mathematician, established the mathematical laws describing the motion of celestial bodies. He determined that planets move in elliptical orbits, not circular ones, around the sun. These are known as Kepler’s Laws:
- 1st Law: Planets move in elliptical orbits with the sun at one focus.
- 2nd Law: A line connecting a planet to the sun sweeps out equal areas during equal intervals of time.
- 3rd Law: The square of a planet’s orbital
Low Voltage Distribution Networks: Aerial and Underground
The distribution network in Low Voltage (LV) begins at processing centers where Medium Voltage (MV) is passed to LV. This network is regulated by Article 8 of the Electrical Regulations for LV and is defined as a set of conductors that, assuming a processing center, runs along the entire supply area of influence.
Types of LV Distribution Networks
LV distribution networks can be one of two types:
- Aerial Network
- Underground Network
Aerial Networks
In aerial networks, conductors can be woven or braided and
Read MoreCosmology and the Expanding Universe: Big Bang & Steady State
Cosmology and the Expanding Universe
Cosmology, a branch of astronomy, studies the structure, origins, and development of the entire universe. Astronomy is the science that studies the stars and components of the universe. Astrophysics studies the composition, structure, and evolution of celestial objects.
Cosmology describes the universe through the application of mathematical models, which are sets of equations used to describe physical systems. These models help to further study the properties
Read MoreUnderstanding Sound and Light: Properties and Effects
Sound: Properties and Characteristics
Sound requires a source (an object that vibrates), a medium for transmission (solid, liquid, or gas), and a receiver. A sound is produced when a body vibrates rapidly. Frequency is the number of complete vibrations or oscillations made in one second. Audible sounds occur when a body vibrates with a frequency between 20 Hz and 20,000 Hz. Sound is transmitted through material means—solid, liquid, or gas—but never through a vacuum.
When an object oscillates to
Read MoreUnderstanding Damping and Vibration Isolation in Mechanical Systems
Plot Variation Between Frequency Ratio and Phase Angle
The critical damping coefficient is the specific value of damping in a system that brings it back to equilibrium as quickly as possible without oscillation. It is given by:
The damping factor, often denoted by ζ, is a dimensionless measure of damping in an oscillating system. It is the ratio of the actual damping coefficient to the critical damping coefficient:
ζ = C/Cc
- ζ < 1: underdamped
- ζ = 1: critically damped
- ζ > 1: overdamped
The logarithmic
Read MoreSound Waves: Propagation, Velocity, and Intensity
Introduction to Sound Waves
Part of the study of physics is the movement of sound. Sound waves, or pressure waves, can only propagate through material media by varying the relative pressure of the medium. Sound, like every wave, has characteristics such as amplitude, frequency, wavelength, and propagation speed. The variations in pressure values compared with any sound wave are very small (measured in dB). The frequency of sound establishes a classification: 20-20,000 Hz is audible sound, below 20
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