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Collision (other)
In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word ''collision'' refers to incidents in which two or more objects collide with great force, the scientific use of the term implies nothing about the magnitude of the force. Types of collisions Collision is short-duration interaction between two bodies or more than two bodies simultaneously causing change in motion of bodies involved due to internal forces acted between them during this. Collisions involve forces (there is a change in velocity). The magnitude of the velocity difference just before impact is called the closing speed. All collisions conserve momentum. What distinguishes different types of collisions is whether they also conserve kinetic energy of the system before and after the collision. Collisions are of three types: #Perfectly inelastic collision. If most or all of the total kinetic energy is lost (diss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collision 9 Block
In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word ''collision'' refers to incidents in which two or more objects collide with great force, the scientific use of the term implies nothing about the magnitude of the force. Some examples of physical interactions that scientists would consider collisions are the following: * When an insect lands on a plant's leaf, its legs are said to collide with the leaf. * When a cat strides across a lawn, each contact that its paws make with the ground is considered a collision, as well as each brush of its fur against a blade of grass. * When a boxer throws a punch, their fist is said to collide with the opponents body. * When an astronomical object merges with a black hole, they are considered to collide. Some colloquial uses of the word collision are the following: * A traffic collision involves at least one automobile. * A mid-a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coefficient Of Restitution
The coefficient of restitution (COR, also denoted by ''e''), is the ratio of the final to initial relative speed between two objects after they collide. It normally ranges from 0 to 1 where 1 would be a perfectly elastic collision. A perfectly inelastic collision has a coefficient of 0, but a 0 value does not have to be perfectly inelastic. It is measured in the Leeb rebound hardness test, expressed as 1000 times the COR, but it is only a valid COR for the test, not as a universal COR for the material being tested. The value is almost always less than 1 due to initial translational kinetic energy being lost to rotational kinetic energy, plastic deformation, and heat. It can be more than 1 if there is an energy gain during the collision from a chemical reaction, a reduction in rotational energy, or another internal energy decrease that contributes to the post-collision velocity. \text (e) = \frac The mathematics were developed by Sir Isaac Newton in 1687. It is also known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projectile
A projectile is an object that is propelled by the application of an external force and then moves freely under the influence of gravity and air resistance. Although any objects in motion through space are projectiles, they are commonly found in warfare and sports (for example, a thrown baseball, kicked football, fired bullet, shot arrow, stone released from catapult). In ballistics mathematical equations of motion are used to analyze projectile trajectories through launch, flight, and impact. Motive force Blowguns and pneumatic rifles use compressed gases, while most other guns and cannons utilize expanding gases liberated by sudden chemical reactions by propellants like smokeless powder. Light-gas guns use a combination of these mechanisms. Railguns utilize electromagnetic fields to provide a constant acceleration along the entire length of the device, greatly increasing the muzzle velocity. Some projectiles provide propulsion during flight by means of a rocket engine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Center Of Momentum Frame
In physics, the center-of-momentum frame (also zero-momentum frame or COM frame) of a system is the unique (up to velocity but not origin) inertial frame in which the total momentum of the system vanishes. The ''center of momentum'' of a system is not a location (but a collection of relative momenta/velocities: a reference frame). Thus "center of momentum" means "center-of-momentum frame" and is a short form of this phrase.Dynamics and Relativity, J.R. Forshaw, A.G. Smith, Wiley, 2009, A special case of the center-of-momentum frame is the center-of-mass frame: an inertial frame in which the center of mass (which is a physical point) remains at the origin. In all COM frames, the center of mass is at rest, but it is not necessarily at the origin of the coordinate system. In special relativity, the COM frame is necessarily unique only when the system is isolated. Properties General The center of momentum frame is defined as the inertial frame in which the sum of the linear moment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inelastic Collision
An inelastic collision, in contrast to an elastic collision, is a collision in which kinetic energy is not conserved due to the action of internal friction. In collisions of macroscopic bodies, some kinetic energy is turned into vibrational energy of the atoms, causing a heating effect, and the bodies are deformed. The molecules of a gas or liquid rarely experience perfectly elastic collisions because kinetic energy is exchanged between the molecules' translational motion and their internal degrees of freedom with each collision. At any one instant, half the collisions are – to a varying extent – inelastic (the pair possesses less kinetic energy after the collision than before), and half could be described as “super-elastic” (possessing ''more'' kinetic energy after the collision than before). Averaged across an entire sample, molecular collisions are elastic. Although inelastic collisions do not conserve kinetic energy, they do obey conservation of momentum. Sim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
If And Only If
In logic and related fields such as mathematics and philosophy, "if and only if" (shortened as "iff") is a biconditional logical connective between statements, where either both statements are true or both are false. The connective is biconditional (a statement of material equivalence), and can be likened to the standard material conditional ("only if", equal to "if ... then") combined with its reverse ("if"); hence the name. The result is that the truth of either one of the connected statements requires the truth of the other (i.e. either both statements are true, or both are false), though it is controversial whether the connective thus defined is properly rendered by the English "if and only if"—with its pre-existing meaning. For example, ''P if and only if Q'' means that ''P'' is true whenever ''Q'' is true, and the only case in which ''P'' is true is if ''Q'' is also true, whereas in the case of ''P if Q'', there could be other scenarios where ''P'' is true and ''Q'' is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dot Product
In mathematics, the dot product or scalar productThe term ''scalar product'' means literally "product with a scalar as a result". It is also used sometimes for other symmetric bilinear forms, for example in a pseudo-Euclidean space. is an algebraic operation that takes two equal-length sequences of numbers (usually coordinate vectors), and returns a single number. In Euclidean geometry, the dot product of the Cartesian coordinates of two vectors is widely used. It is often called the inner product (or rarely projection product) of Euclidean space, even though it is not the only inner product that can be defined on Euclidean space (see Inner product space for more). Algebraically, the dot product is the sum of the products of the corresponding entries of the two sequences of numbers. Geometrically, it is the product of the Euclidean magnitudes of the two vectors and the cosine of the angle between them. These definitions are equivalent when using Cartesian coordinates. In mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newton's Laws Of Motion
Newton's laws of motion are three basic laws of classical mechanics that describe the relationship between the motion of an object and the forces acting on it. These laws can be paraphrased as follows: # A body remains at rest, or in motion at a constant speed in a straight line, unless acted upon by a force. # When a body is acted upon by a force, the time rate of change of its momentum equals the force. # If two bodies exert forces on each other, these forces have the same magnitude but opposite directions. The three laws of motion were first stated by Isaac Newton in his '' Philosophiæ Naturalis Principia Mathematica'' (''Mathematical Principles of Natural Philosophy''), originally published in 1687. Newton used them to investigate and explain the motion of many physical objects and systems, which laid the foundation for classical mechanics. In the time since Newton, the conceptual content of classical physics has been reformulated in alternative ways, involving diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolling Friction
Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation (or movement) of the wheel, roadbed, etc., is recovered when the pressure is removed. Two forms of this are hysteresis losses (see below), and permanent (plastic) deformation of the object or the surface (e.g. soil). Note that the slippage between the wheel and the surface also results in energy dissipation. Although some researchers have included this term in rolling resistance, some suggest that this dissipation term should be treated separately from rolling resistance because it is due to the applied torque to the wheel and the resultant slip between the wheel and ground, which is called slip loss or slip resistance. In addition, only the so-called slip resistance involves friction, therefore the name "rolling frict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Billiard Balls
A billiard ball is a small, hard ball used in cue sports, such as carom billiards, pool, and snooker. The number, type, diameter, color, and pattern of the balls differ depending upon the specific game being played. Various particular ball properties such as hardness, friction coefficient, and resilience are important to accuracy. History Early balls were made of various materials, including wood and clay (the latter remaining in use well into the 20th century). Although affordable ox-bone balls were in common use in Europe, elephant ivory was favored since at least 1627 until the early 20th century; the earliest known written reference to ivory billiard balls is in the 1588 inventory of the Duke of Norfolk. Dyed and numbered balls appeared around the early 1770s. By the mid-19th century, elephants were being slaughtered for their ivory at an alarming rate, just to keep up with the demand for high-end billiard balls – no more than eight balls could be made from a single e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cue Sports
Cue sports are a wide variety of games of skill played with a cue, which is used to strike billiard balls and thereby cause them to move around a cloth-covered table bounded by elastic bumpers known as . There are three major subdivisions of games within cue sports: *Carom billiards, played on tables without , typically 10 feet in length, including straight rail, balkline, one-cushion carom, three-cushion billiards, artistic billiards, and four-ball *Pool, played on six-pocket tables of 7-, 8-, 9-, or 10-foot length, including among others eight-ball (the world's most widely played cue sport), nine-ball (the dominant professional game), ten-ball, straight pool (the formerly dominant pro game), one-pocket, and bank pool *Snooker, English billiards, and Russian pyramid, played on a large, six-pocket table (dimensions just under 12 ft by 6 ft), all of which are classified separately from pool based on distinct development histories, player culture, rules, and termi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
