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Free Fall
In classical mechanics, free fall is any motion of a physical object, body where gravity is the only force acting upon it. A freely falling object may not necessarily be falling down in the vertical direction. If the common definition of the word "fall" is used, an object moving upwards is not considered to be falling, but using scientific definitions, if it is subject to only the force of gravity, it is said to be in free fall. The Moon is thus in free fall around the Earth, though its orbital speed keeps it in orbit of the Moon, very far orbit from the Earth's surface. In a roughly uniform gravitational field gravity acts on each part of a body approximately equally. When there are no other forces, such as the normal force exerted between a body (e.g. an astronaut in orbit) and its surrounding objects, it will result in the sensation of weightlessness, a condition that also occurs when the gravitational field is weak (such as when far away from any source of gravity). The ter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical Mechanics
Classical mechanics is a Theoretical physics, physical theory describing the motion of objects such as projectiles, parts of Machine (mechanical), machinery, spacecraft, planets, stars, and galaxies. The development of classical mechanics involved Scientific Revolution, substantial change in the methods and philosophy of physics. The qualifier ''classical'' distinguishes this type of mechanics from physics developed after the History of physics#20th century: birth of modern physics, revolutions in physics of the early 20th century, all of which revealed limitations in classical mechanics. The earliest formulation of classical mechanics is often referred to as Newtonian mechanics. It consists of the physical concepts based on the 17th century foundational works of Sir Isaac Newton, and the mathematical methods invented by Newton, Gottfried Wilhelm Leibniz, Leonhard Euler and others to describe the motion of Physical body, bodies under the influence of forces. Later, methods bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminal Velocity
Terminal velocity is the maximum speed attainable by an object as it falls through a fluid (air is the most common example). It is reached when the sum of the drag force (''Fd'') and the buoyancy is equal to the downward force of gravity (''FG'') acting on the object. Since the net force on the object is zero, the object has zero acceleration. For objects falling through air at normal pressure, the buoyant force is usually dismissed and not taken into account, as its effects are negligible. As the speed of an object increases, so does the drag force acting on it, which also depends on the substance it is passing through (for example air or water). At some speed, the drag or force of resistance will be equal to the gravitational pull on the object. At this point the object stops accelerating and continues falling at a constant speed called the terminal velocity (also called settling velocity). An object moving downward faster than the terminal velocity (for example because it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Clock
A water clock, or clepsydra (; ; ), is a timepiece by which time is measured by the regulated flow of liquid into (inflow type) or out from (outflow type) a vessel, and where the amount of liquid can then be measured. Water clocks are some of the oldest time-measuring instruments. The simplest form of water clock, with a bowl-shaped outflow, existed in Babylon, Egypt, and Persia around the 16th century BC. Other regions of the world, including India and China, also provide early evidence of water clocks, but the earliest dates are less certain. Water clocks were used in ancient Greece and in ancient Rome, as described by technical writers such as Ctesibius (died 222 BC) and Vitruvius (died after 15 BC). Designs A water clock uses the flow of water to measure time. If viscosity is neglected, the physical principle required to study such clocks is Torricelli's law. Two types of water clock exist: inflow and outflow. In an outflow water clock, a container is filled with wate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galileo's Leaning Tower Of Pisa Experiment
Between 1589 and 1592, the Italian scientist Galileo Galilei (then professor of mathematics at the University of Pisa) is said to have dropped "unequal weights of the same material" from the Leaning Tower of Pisa to demonstrate that their time of descent was independent of their mass, according to a biography by Galileo's pupil Vincenzo Viviani, composed in 1654 and published in 1717. Vincenzo Viviani (1717), ''Racconto istorico della vita di Galileo Galilei'', p. 606: [...dimostrando ciò con replicate esperienze, fatte dall'altezza del Campanile di Pisa con l'intervento delli altri lettori e filosofi e di tutta la scolaresca... [...Galileo showed this [all bodies, whatever their weights, fall with equal speeds] by repeated experiments made from the height of the Leaning Tower of Pisa in the presence of other professors and all the students...]. The basic premise had already been demonstrated by Italian experimenters a few decades earlier. According to the story, Galileo discov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dictionary Of Scientific Biography
The ''Dictionary of Scientific Biography'' is a scholarly reference work that was published from 1970 through 1980 by publisher Charles Scribner's Sons, with main editor the science historian Charles Coulston Gillispie, Charles Gillispie, from Princeton University. It consisted of sixteen volumes. It is supplemented by the ''New Dictionary of Scientific Biography'' (2007). Both these publications are included in a later ebook, electronic book, called the ''Complete Dictionary of Scientific Biography''. ''Dictionary of Scientific Biography'' The ''Dictionary of Scientific Biography'' is a scholarly English-language reference work consisting of biography, biographies of scientists from antiquity to modern times but excluding scientists who were alive when the ''Dictionary'' was first published. It includes scientists who worked in the areas of mathematics, physics, chemistry, biology, and earth sciences. The work is notable for being one of the most substantial reference works in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shlomo Pines
Shlomo Pines (; ; 5 August 1908 – 9 January 1990) was an Israeli scholar of Jewish and Islamic philosophy, best known for his English translation of Maimonides' '' Guide of the Perplexed''. Biography Pines was born in Charenton-le-Pont near Paris, and grew up in Paris, Riga, Arkhangelsk, London and Berlin. His father, Meir Pines, was a scholar and businessman whose Sorbonne dissertation comprised the first attempt at a history of Yiddish literature. Between 1926 and 1934 Shlomo Pines studied philosophy, Semitic languages, and linguistics at the universities of Heidelberg, Geneva and Berlin. Among his friends at Berlin were Paul Kraus and Leo Strauss, the latter of whom would contribute the lengthy introductory essay to Pines' classic translation of '' The Guide''. From 1937 to 1939 he taught the history of science in Islamic countries at the Institute of the History of Science in Paris. In 1940, he and his family departed for Palestine on the last boat leaving Marseille ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Acceleration
In physics, gravitational acceleration is the acceleration of an object in free fall within a vacuum (and thus without experiencing drag (physics), drag). This is the steady gain in speed caused exclusively by gravitational attraction. All bodies accelerate in vacuum at the same rate, regardless of the masses or compositions of the bodies; the measurement and analysis of these rates is known as gravimetry. At a fixed point on the surface, the magnitude of gravity of Earth, Earth's gravity results from combined effect of gravitation and the centrifugal force from Earth's rotation. At different points on Earth's surface, the free fall acceleration ranges from , depending on altitude, latitude, and longitude. A conventional standard gravity, standard value is defined exactly as 9.80665 m/s² (about 32.1740 ft/s²). Locations of significant variation from this value are known as gravity anomaly, gravity anomalies. This does not take into account other effects, such as buoyancy or d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abu'l-Barakāt Al-Baghdādī
Abu'l-Barakāt Hibat Allah ibn Malkā al-Baghdādī (; c. 1080 – 1164 or 1165 CE) was an Islamic philosopher, physician and physicist of Jewish descent from Baghdad, Iraq. Abu'l-Barakāt, an older contemporary of Maimonides, was originally known by his Hebrew birth name Baruch ben Malka and was given the name of Nathanel by his pupil Isaac ben Ezra before his conversion from Judaism to Islam later in his life. His writings include the anti-Aristotelian philosophical work ''Kitāb al-Muʿtabar'' ("The Book of What Has Been Established by Personal Reflection"); a philosophical commentary on the Kohelet; and the treatise "On the Reason Why the Stars Are Visible at Night and Hidden in Daytime". Abu'l-Barakāt was an Aristotelian philosopher who in many respects followed Ibn Sina, but also developed his own ideas. He proposed an explanation of the acceleration of falling bodies by the accumulation of successive increments of power with successive increments of velocity. His th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Philoponus
John Philoponus ( Greek: ; , ''Ioánnis o Philóponos''; c. 490 – c. 570), also known as John the Grammarian or John of Alexandria, was a Coptic Miaphysite philologist, Aristotelian commentator and Christian theologian from Alexandria, Byzantine Egypt, who authored a number of philosophical treatises and theological works. John Philoponus broke from the Aristotelian– Neoplatonic tradition, questioning methodology and eventually leading to empiricism in the natural sciences. He was one of the first to propose a "theory of impetus" similar to the modern concept of inertia over Aristotelian dynamics. He is also the historical founder of what is now called the Kalam cosmological argument. Later in life Philoponus turned to Christian apologetics, arguing against the eternity of the world in his '' De opificio mundi'', a theory which formed the basis of pagan attacks on the Christian doctrine of Creation. He also wrote on Christology and was posthumously condemned as a here ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aristotelian Physics
Aristotelian physics is the form of natural philosophy described in the works of the Greek philosopher Aristotle (384–322 BC). In his work ''Physics'', Aristotle intended to establish general principles of change that govern all natural bodies, both living and inanimate, celestial and terrestrialincluding all motion (change with respect to place), quantitative change (change with respect to size or number), qualitative change, and substantial change (" coming to be" existence.html" ;"title="oming into existence">oming into existence, 'generation'or "passing away" [no longer existing, 'corruption']). To Aristotle, 'physics' was a broad field including subjects which would now be called the philosophy of mind, sensory experience, memory, anatomy and biology. It constitutes the foundation of the thought underlying many of his works. Key concepts of Aristotelian physics include the structuring of the cosmos into concentric spheres, with the Earth at the centre and celestial spher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanics
Mechanics () is the area of physics concerned with the relationships between force, matter, and motion among Physical object, physical objects. Forces applied to objects may result in Displacement (vector), displacements, which are changes of an object's position relative to its environment. Theoretical expositions of this branch of physics has its origins in Ancient Greece, for instance, in the writings of Aristotle and Archimedes (see History of classical mechanics and Timeline of classical mechanics). During the early modern period, scientists such as Galileo Galilei, Johannes Kepler, Christiaan Huygens, and Isaac Newton laid the foundation for what is now known as classical mechanics. As a branch of classical physics, mechanics deals with bodies that are either at rest or are moving with velocities significantly less than the speed of light. It can also be defined as the physical science that deals with the motion of and forces on bodies not in the quantum realm. History ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics (Aristotle)
The ''Physics'' (; or , possibly meaning " Lectures on nature") is a named text, written in ancient Greek, collated from a collection of surviving manuscripts known as the Corpus Aristotelicum, attributed to the 4th-century BC philosopher Aristotle. The meaning of physics in Aristotle It is a collection of treatises or lessons that deals with the most general (philosophical) principles of natural or moving things, both living and non-living, rather than physical theories (in the modern sense) or investigations of the particular contents of the universe. The chief purpose of the work is to discover the principles and causes of (and not merely to describe) change, or movement, or motion (κίνησις ''kinesis''), especially that of natural wholes (mostly living things, but also inanimate wholes like the cosmos). In the conventional Andronicean ordering of Aristotle's works, it stands at the head of, as well as being foundational to, the long series of physical, cosmolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
