Brownian motion is the random motion of particles suspended in a medium.
In Newtonian mechanics, momentum is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If m is an object's mass and v is its velocity, then the object's momentum p is:
In physics, the special theory of relativity, or special relativity for short, is a scientific theory of the relationship between space and time. In Albert Einstein's 1905 treatment, the theory is presented as being based on just two postulates:
- The laws of physics are invariant (identical) in all inertial frames of reference.
- The speed of light in vacuum is the same for all observers, regardless of the motion of light source or observer.
In physics, spacetime is a mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum. Spacetime diagrams are useful in visualizing and understanding relativistic effects, such as how different observers perceive where and when events occur.
In physics, the twin paradox is a thought experiment in special relativity involving identical twins, one of whom makes a journey into space in a high-speed rocket and returns home to find that the twin who remained on Earth has aged more. This result appears puzzling because each twin sees the other twin as moving, and so, as a consequence of an incorrect and naive application of time dilation and the principle of relativity, each should paradoxically find the other to have aged less. However, this scenario can be resolved within the standard framework of special relativity: the travelling twin's trajectory involves two different inertial frames, one for the outbound journey and one for the inbound journey. Another way of looking at it is to realize the travelling twin is undergoing acceleration, which makes them a non-inertial observer. In both views there is no symmetry between the spacetime paths of the twins. Therefore, the twin paradox is not actually a paradox in the sense of a logical contradiction. There is still debate as to the resolution of the twin paradox.
Ohm's law states that the electric current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, one arrives at the three mathematical equations used to describe this relationship:
The Boltzmann constant is the proportionality factor that relates the average relative thermal energy of particles in a gas with the thermodynamic temperature of the gas. It occurs in the definitions of the kelvin (K) and the gas constant, and in Planck's law of black-body radiation and Boltzmann's entropy formula, and is used in calculating thermal noise in resistors. The Boltzmann constant has dimensions of energy divided by temperature, the same as entropy. It is named after the Austrian scientist Ludwig Boltzmann.
In physics, equations of motion are equations that describe the behavior of a physical system in terms of its motion as a function of time. More specifically, the equations of motion describe the behavior of a physical system as a set of mathematical functions in terms of dynamic variables. These variables are usually spatial coordinates and time, but may include momentum components. The most general choice are generalized coordinates which can be any convenient variables characteristic of the physical system. The functions are defined in a Euclidean space in classical mechanics, but are replaced by curved spaces in relativity. If the dynamics of a system is known, the equations are the solutions for the differential equations describing the motion of the dynamics.
In thermodynamics, the Gibbs free energy is a thermodynamic potential that can be used to calculate the maximum amount of work, other than pressure-volume work, that may be performed by a thermodynamically closed system at constant temperature and pressure. It also provides a necessary condition for processes such as chemical reactions that may occur under these conditions. The Gibbs free energy is expressed as
Ipsus or Ipsos or Ipsous (Ἴψους), was a town of ancient Phrygia a few miles below Synnada. The place itself never was of any particular note, but it is celebrated in history for the great battle fought in its plains, in 301 BCE, by the aged Antigonus and his son Demetrius against the combined forces of Cassander, Lysimachus, and Seleucus, in which Antigonus lost his conquests and his life. From Hierocles and the Acts of Councils, we learn that in the seventh and eighth centuries it was the see of a Christian bishop. No longer the seat of a residential bishop, Ipsus remains a titular see of the Roman Catholic Church.
Faraday's law of induction is a law of electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an electromotive force (emf). This phenomenon, known as electromagnetic induction, is the fundamental operating principle of transformers, inductors, and many types of electric motors, generators and solenoids.
The Syrian Communist Party is an anti-revisionist Marxist–Leninist communist party in Syria. The party emerged from a split in the Syrian Communist Party in 1986, as formed by the anti-Perestroika faction led by Khalid Bakdash. Khalid Bakdash died in 1995 and was succeeded as secretary of his party faction by his widow, Wisal Farha Bakdash. At the time of the 2000 Damascus Spring, the party was able to publish a newspaper called Sawt al-Shaab.
Pavel Golia was a Slovenian poet and playwright.
In fluid dynamics, drag, sometimes referred to as fluid resistance, is a force acting opposite to the relative motion of any object, moving with respect to a surrounding fluid. This can exist between two fluid layers, two solid surfaces, or between a fluid and solid surface. Drag forces tend to decrease fluid velocity relative to the solid object in the fluid's path.
Mun Bhuridatta was a Thai bhikkhu from Isan region who is credited, along with his mentor, Ajahn Sao Kantasīlo, with establishing the Thai Forest Tradition or "Kammaṭṭhāna tradition" that subsequently spread throughout Thailand and to several countries abroad.
Antigonia also transliterated as Antigonea and Antigoneia was a Hellenistic city in Seleucid Empire, Syria, on the Orontes, founded by Antigonus I Monophthalmus in 307 BC, and intended to be the capital of his empire; the site is approximately 7 km northeast of Antakya, Hatay Province, Turkey. After the Battle of Ipsus, 301 BC, in which Antigonus perished, the inhabitants of Antigonia were removed by his successful rival Seleucus I Nicator to the city of Antioch, which Seleucus founded a little lower down the river. Diodorus erroneously says that the inhabitants were removed to Seleucia Pieria. Antigonia continued, however, to exist, and is mentioned in the war with the Parthians after the defeat of Crassus.
Ernst Jakob Henne was a German motorcycle racer and racecar driver.
Classical mechanics is a physical theory describing the motion of objects such as projectiles, parts of machinery, spacecraft, planets, stars, and galaxies. The development of classical mechanics involved substantial change in the methods and philosophy of physics. The qualifier classical distinguishes this type of mechanics from physics developed after the revolutions in physics of the early 20th century, all of which revealed limitations in classical mechanics.
The Drill Master diving accident was an incident in Norway in January 1974 that resulted in the death of two commercial divers. During a two-man dive from the North Sea rig Drill Master, the diving bell's drop weight was accidentally released, causing the bell to surface from a depth of 320 feet (98 m) with its bottom door open and drag the diver working outside through the water on his umbilical. The two divers, Per Skipnes and Robert John Smyth, both died from rapid decompression and drowning. The accident was caused by instructions aboard Drill Master which had not been updated when the bell system was modified and which stated that a valve should be closed during the dive which should have been open. Skipnes' body was never recovered.
Hassan Aourid is a Moroccan writer. He was born in Errachidia. He has a PhD in political science and lectures at the Mohammed V University. He has published widely in both Arabic and French. He has written half a dozen novels:
