Relativistic speed refers to speed at which relativistic effects become significant to the desired accuracy of measurement of the phenomenon being observed.
 Relativistic effects are those discrepancies between values calculated by models considering and not considering relativity.
 Related words are velocity, rapidity, and celerity which is proper velocity.
 Speed is a scalar, being the magnitude of the velocity vector which in relativity is the four-velocity and in three-dimension Euclidean space a three-velocity.
 Speed is empirically measured as average speed, although current devices in common use can estimate speed over very small intervals and closely approximate instantaneous speed.
 Non-relativistic discrepancies include cosine error which occurs in speed detection devices when only one scalar component of the three-velocity is measured and the Doppler effect which may affect observations of wavelength and frequency.Relativistic effects are highly non-linear and for everyday purposes are insignificant because the Newtonian model closely approximates the relativity model.
 In special relativity the Lorentz factor is a measure of time dilation, length contraction and relativistic mass increase of a moving object.
The Mercurial Vapor is a football boot manufactured by Nike.
 The boot is known for being lightweight.
 Because of this, the boot is endorsed by many players for whom speed is part of their game, notably wingers or strikers, such as Cristiano Ronaldo, Franck Ribéry, Luiz Adriano, Zlatan Ibrahimović, Didier Drogba, Jesús Navas, Luka Modrić, Arturo Vidal, Douglas Costa, Xherdan Shaqiri, Raheem Sterling, Stephan El Shaarawy, Eden Hazard, Alexis Sánchez, Carlos Bacca and Philippe Coutinho, among others.
Wife Acceptance Factor, Wife Approval Factor, or Wife Appeal Factor (WAF) is an assessment of design elements that either increase or diminish the likelihood a wife will approve the purchase of expensive consumer electronics products such as high-fidelity loudspeakers, home theater systems and personal computers. Stylish, compact forms and appealing colors are commonly considered to have a high WAF.
 The term is a tongue-in-cheek play on electronics jargon such as "form factor" and "power factor" and derives from the gender stereotype that men are predisposed to appreciate gadgetry and performance criteria whereas women must be wooed by visual and aesthetic factors.
Development speed describes how fast a programmer can program.
 Most of the time development speed refers to the speed that a programmer can program with a particular programming language.
 It's a crucial factor of productivity of a programming language.
 Application speed is often compared with development speed when programming languages are discussed.
 For example, Python has a high development speed but a poor application speed.
 C has a low development speed but a good application speed.
Relativistic rocket refers to any spacecraft that travels at a velocity close enough to light speed for relativistic effects to become significant.
 The meaning of "significant" is a matter of context, but generally speaking a velocity of at least 50% of the speed of light (0.5"c") is required.
 The Lorentz factor - also known as the "gamma" factor, γ, and present in the equations for time dilation, relativistic mass, and length contraction - is equal to 1.15 at 0.5"c".
 Above this speed special relativity is required to accurately describe motion, whereas below this speed sufficient accuracy is provided by Newtonian physics and the Tsiolkovsky rocket equation.
The velocity factor (VF), also called wave propagation speed or velocity of propagation (VoP or formula_1), of a transmission medium is the ratio of the speed at which a wavefront (of an acoustic signal, for example, or an electromagnetic signal, a radio signal, a light pulse in an optical fibre or a change of the electrical voltage on a copper wire) passes through the medium, to the speed of light in a vacuum.
 For optical signals, the velocity factor is the reciprocal of the refractive index.
Alexis Alejandro Sánchez Sánchez (] ; born 19 December 1988), also known as simply Alexis, is a Chilean professional footballer who plays as a forward for English club Arsenal and the Chile national team.
Factor VII (EC 3.4.21.21 , "blood-coagulation factor VIIa", "activated blood coagulation factor VII", formerly known as proconvertin) is one of the proteins that causes blood to clot in the coagulation cascade.
 It is an enzyme of the serine protease class.
 A recombinant form of human factor VIIa (eptacog alfa [activated], NovoSeven) has U.S. Food and Drug Administration approval for uncontrolled bleeding in hemophilia patients.
 It is sometimes used unlicensed in severe uncontrollable bleeding, although there have been safety concerns.
 A biosimilar form of recombinant activated factor VII (AryoSeven) is also available, but does not play any considerable role in the market.
A quantum field effect transistor (QFET) is a kind of field-effect transistor that takes advantage of quantum tunneling to greatly increase the speed of transistor operation by eliminating the traditional transistor's area of electron conduction which typically causes carriers to slow down by a factor of 3000.
 The result is an increase in logic speed by a factor of 10 with a simultaneous reduction in component power requirement and size also by a factor of 10.
 It achieves these things through a manufacturing process known as rapid thermal processing (RTP) that uses ultrafine layers of construction materials.
A healing factor is the ability of some characters in fiction to recover from bodily injuries or disease at a superhuman rate.
 Since the introduction of Wolverine by Marvel Comics in 1974 and inspired by the immense popularity of the character, superhuman healing has become a fairly common power featured in comic books, novels, television, film, and other media.
 The overall efficiency of a character's healing factor often fluctuates due to various writers applying a very broad degree of artistic license.
 Weapon X has been established, on multiple accounts for having the fastest healing factor over all mutants, with the exception of external factors.
 As a result, especially concerning characters depicted in comic books, it has become a very common source of debate among fans.
 Over the years, it has also become common for healing factors to have an umbrella effect, serving as a partial source for multiple superhuman abilities; various powers thus demonstrated include superhuman strength, speed, stamina, agility, reflexes, durability and/or senses, to name the most common.
 The source of a character's healing factor, depending upon the medium, usually ranges from natural genetic mutation, accidental exposure to radioactive materials, artificially-induced genetic enhancement, cybernetic augmentation, magic or even a combination of different factors.
 Despite the ability to quickly recover from wounds, characters with a healing factor are still capable of feeling pain.

Question: What position does alexis sanchez play and is speed a factor?
Answer: Alexis, is a Chilean professional footballer who plays as a forward