Angular velocityIn physics, angular velocity (symbol ω, sometimes Ω), also known as angular frequency vector, is a pseudovector representation of how the angular position or orientation of an object changes with time, i.e. how quickly an object rotates (spins or revolves) around an axis of rotation and how fast the axis itself changes direction. The magnitude of the pseudovector, , represents the angular speed (or angular frequency), the rate at which the object rotates (spins or revolves).
Angular momentumIn physics, angular momentum (sometimes called moment of momentum or rotational momentum) is the rotational analog of linear momentum. It is an important physical quantity because it is a conserved quantity – the total angular momentum of a closed system remains constant. Angular momentum has both a direction and a magnitude, and both are conserved. Bicycles and motorcycles, flying discs, rifled bullets, and gyroscopes owe their useful properties to conservation of angular momentum.
Angular accelerationIn physics, angular acceleration (symbol α, alpha) is the time rate of change of angular velocity. Following the two types of angular velocity, spin angular velocity and orbital angular velocity, the respective types of angular acceleration are: spin angular acceleration, involving a rigid body about an axis of rotation intersecting the body's centroid; and orbital angular acceleration, involving a point particle and an external axis. Angular acceleration has physical dimensions of angle per time squared, measured in SI units of radians per second squared (rads-2).
Rotation formalisms in three dimensionsIn geometry, various formalisms exist to express a rotation in three dimensions as a mathematical transformation. In physics, this concept is applied to classical mechanics where rotational (or angular) kinematics is the science of quantitative description of a purely rotational motion. The orientation of an object at a given instant is described with the same tools, as it is defined as an imaginary rotation from a reference placement in space, rather than an actually observed rotation from a previous placement in space.
RotationRotation or rotational motion is the circular movement of an object around a central line, known as axis of rotation. A plane figure can rotate in either a clockwise or counterclockwise sense around a perpendicular axis intersecting anywhere inside or outside the figure at a center of rotation. A solid figure has an infinite number of possible axes and angles of rotation, including chaotic rotation (between arbitrary orientations), in contrast to rotation around a axis.
Angular frequencyIn physics, angular frequency (symbol ω), also called angular speed and angular rate, is a scalar measure of the angle rate (the angle per unit time) or the temporal rate of change of the phase argument of a sinusoidal waveform or sine function (for example, in oscillations and waves). Angular frequency (or angular speed) is the magnitude of the pseudovector quantity angular velocity. Angular frequency can be obtained multiplying rotational frequency, ν (or ordinary frequency, f) by a full turn (2π radians): ω=2π radν.
Rotation (mathematics)Rotation in mathematics is a concept originating in geometry. Any rotation is a motion of a certain space that preserves at least one point. It can describe, for example, the motion of a rigid body around a fixed point. Rotation can have a sign (as in the sign of an angle): a clockwise rotation is a negative magnitude so a counterclockwise turn has a positive magnitude. A rotation is different from other types of motions: translations, which have no fixed points, and (hyperplane) reflections, each of them having an entire (n − 1)-dimensional flat of fixed points in a n-dimensional space.
Plane of rotationIn geometry, a plane of rotation is an abstract object used to describe or visualize rotations in space. The main use for planes of rotation is in describing more complex rotations in four-dimensional space and higher dimensions, where they can be used to break down the rotations into simpler parts. This can be done using geometric algebra, with the planes of rotations associated with simple bivectors in the algebra.
Anonymous P2PAn anonymous P2P communication system is a peer-to-peer distributed application in which the nodes, which are used to share resources, or participants are anonymous or pseudonymous. Anonymity of participants is usually achieved by special routing overlay networks that hide the physical location of each node from other participants. Interest in anonymous P2P systems has increased in recent years for many reasons, ranging from the desire to share files without revealing one's network identity and risking litigation to distrust in governments, concerns over mass surveillance and data retention, and lawsuits against bloggers.
Quaternions and spatial rotationUnit quaternions, known as versors, provide a convenient mathematical notation for representing spatial orientations and rotations of elements in three dimensional space. Specifically, they encode information about an axis-angle rotation about an arbitrary axis. Rotation and orientation quaternions have applications in computer graphics, computer vision, robotics, navigation, molecular dynamics, flight dynamics, orbital mechanics of satellites, and crystallographic texture analysis.
Anonymous remailerAn anonymous remailer is a server that receives messages with embedded instructions on where to send them next, and that forwards them without revealing where they originally came from. There are cypherpunk anonymous remailers, mixmaster anonymous remailers, and nym servers, among others, which differ in how they work, in the policies they adopt, and in the type of attack on the anonymity of e-mail they can (or are intended to) resist. Remailing as discussed in this article applies to e-mails intended for particular recipients, not the general public.
Anonymous blogAn anonymous blog is a blog without any acknowledged author or contributor. Anonymous bloggers may achieve anonymity through the simple use of a pseudonym, or through more sophisticated techniques such as layered encryption routing, manipulation of post dates, or posting only from publicly accessible computers. Motivations for posting anonymously include a desire for privacy or fear of retribution by an employer (e.g., in whistleblower cases), a government (in countries that monitor or censor online communication), or another group.
Anonymous proxyAn anonymizer or an anonymous proxy is a tool that attempts to make activity on the Internet untraceable. It is a proxy server computer that acts as an intermediary and privacy shield between a client computer and the rest of the Internet. It accesses the Internet on the user's behalf, protecting personal information of the user by hiding the client computer's identifying information. Anonymous proxy is the opposite of transparent proxy, which sends user information in the connection request header.
GreenGreen is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 nm. In subtractive color systems, used in painting and color printing, it is created by a combination of yellow and cyan; in the RGB color model, used on television and computer screens, it is one of the additive primary colors, along with red and blue, which are mixed in different combinations to create all other colors.
General officerA general officer is an officer of high rank in the armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers to a rank above colonel. The term general is used in two ways: as the generic title for all grades of general officer and as a specific rank. It originates in the 16th century, as a shortening of captain general, which rank was taken from Middle French capitaine général.
Green politicsGreen politics, or ecopolitics, is a political ideology that aims to foster an ecologically sustainable society often, but not always, rooted in environmentalism, nonviolence, social justice and grassroots democracy. It began taking shape in the western world in the 1970s; since then green parties have developed and established themselves in many countries around the globe and have achieved some electoral success. The political term green was used initially in relation to die Grünen (German for "the Greens"), a green party formed in the late 1970s.
Green partyA green party is a formally organized political party based on the principles of green politics, such as social justice, environmentalism and nonviolence. Green party platforms typically embrace social democratic economic policies and form coalitions with other left-wing parties. Green parties exist in nearly 90 countries around the world, many of which are members of Global Greens. There are distinctions between "green" parties and "Green" parties. Any party, faction, or politician may be labeled "green" if it emphasizes environmental causes.
Brigadier generalBrigadier general or Brigade general is a military rank used in many countries. The rank is usually above a colonel, and below a major general or divisional general. When appointed to a field command, a brigadier general is typically in command of a brigade consisting of around 4,000 troops (four battalions). Brigadier general (Brig. Gen.) is a military rank used in many countries. It is the lowest ranking general officer in some countries, usually sitting between the ranks of colonel and major general.
Red–green allianceIn politics, a red–green alliance or red–green coalition is an alliance of "red" (often social-democratic or democratic socialist) parties with "green" (often green and/or occasionally agrarian) parties. The alliance is often based on common left political views, especially a shared distrust of corporate or capitalist institutions. While the "red" social-democratic parties tend to focus on the effects of capitalism on the working class, the "green" environmentalist parties tend to focus on the environmental effects of capitalism.
Colonel generalColonel general is a three- or four-star military rank used in some armies. It is particularly associated with Germany, where historically general officer ranks were one grade lower than in the Commonwealth and the United States, and Generaloberst was a rank above full General, but below Generalfeldmarschall. The rank of colonel general also exists in the armed forces organized along the lines of the Soviet model, where it is comparable to that of a lieutenant general in many NATO armed forces (rank code OF-8).
