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Archimedes was born c. 287 BC in the seaport city of Syracuse, Sicily, at that time a self-governing colony in Magna Graecia. The date of birth is based on a statement by the Byzantine Greek scholar John Tzetzes that Archimedes lived for 75 years before his death in 212 BC. [8] In the Sand-Reckoner, Archimedes gives his father's name as Phidias ...
Cycloid. In geometry, a cycloid is the curve traced by a point on a circle as it rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another curve. The cycloid, with the cusps pointing upward, is the curve of fastest descent under uniform ...
The Penrose triangle, also known as the Penrose tribar, the impossible tribar, [1] or the impossible triangle, [2] is a triangular impossible object, an optical illusion consisting of an object which can be depicted in a perspective drawing. It cannot exist as a solid object in ordinary three-dimensional Euclidean space, although its surface ...
Gauss's law for gravity can be derived from Newton's law of universal gravitation, which states that the gravitational field due to a point mass is: where. er is the radial unit vector, r is the radius, | r |. M is the mass of the particle, which is assumed to be a point mass located at the origin.
An O'Neill cylinder (also called an O'Neill colony) is a space settlement concept proposed by American physicist Gerard K. O'Neill in his 1976 book The High Frontier: Human Colonies in Space. [ 1 ] O'Neill proposed the colonization of space for the 21st century, using materials extracted from the Moon and later from asteroids. [ 2 ]
In projective geometry, a cylinder is simply a cone whose apex (vertex) lies on the plane at infinity. If the cone is a quadratic cone, the plane at infinity (which passes through the vertex) can intersect the cone at two real lines, a single real line (actually a coincident pair of lines), or only at the vertex.
In physics and engineering, a free body diagram (FBD; also called a force diagram) [1] is a graphical illustration used to visualize the applied forces, moments, and resulting reactions on a free body in a given condition. It depicts a body or connected bodies with all the applied forces and moments, and reactions, which act on the body (ies).
Einstein's thought experiments. A hallmark of Albert Einstein 's career was his use of visualized thought experiments (German: Gedankenexperiment[1]) as a fundamental tool for understanding physical issues and for elucidating his concepts to others. Einstein's thought experiments took diverse forms. In his youth, he mentally chased beams of light.