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Volleyball Float Serve
The float serve is one of the types of serves in the game of volleyball. The serve involves hitting the volleyball in such a way to minimize the rotation of the ball, causing unpredictability in the ball’s movement and is akin to baseball's knuckleball. During this serve, the ball is moving in the air without spin, allowing drag, lift, and turbulent air flow to have a big effect on its movement. When done correctly, the float serve is hard for opponents to predict where the ball will end up, thus rendering it hard to pass. The effectiveness of the float serve is determined by its ability to succeed in an ace, or winning the point by serving over the net and having the ball hit the ground before the opponent can touch it. Factors Rotation of volleyball Float serves are only possible with minimal to no spin of the volleyball while it is moving in the air. Unlike a topspin serve, which uses the spin of the ball to create a constant difference in pressure that drives the ball downw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volleyball
Volleyball is a team sport in which two teams of six players are separated by a net. Each team tries to score points by grounding a ball on the other team's court under organized rules. It has been a part of the official program of the Summer Olympic Games since Tokyo 1964. Beach volleyball was introduced to the programme at the Atlanta 1996. The adapted version of volleyball at the Summer Paralympic Games is sitting volleyball. The complete set of rules is extensive, but play essentially proceeds as follows: a player on one of the teams begins a 'rally' by serving the ball (tossing or releasing it and then hitting it with a hand or arm), from behind the back boundary line of the court, over the net, and into the receiving team's court. The receiving team must not let the ball be grounded within their court. The team may touch the ball up to three times to return the ball to the other side of the court, but individual players may not touch the ball twice consecutively. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knuckleball
A knuckleball or knuckler is a baseball pitch thrown to minimize the spin of the ball in flight, causing an erratic, unpredictable motion. The air flow over a seam of the ball causes the ball to change from laminar to turbulent flow. This change adds a deflecting force to the baseball, making it difficult for batters to hit but also difficult for pitchers to control and catchers to catch; umpires are challenged as well, as the ball's irregular motion through the air makes it harder to call balls and strikes.Hoffman, Benjamin"Not So Easy on the Eyes"''New York Times'' (June 23, 2012) A pitcher who throws knuckleballs is known as a knuckleballer. Origins The origins of the knuckleball are unclear. Toad Ramsey of the Louisville Colonels in the old American Association—his pitch likely resembled the knuckle curve—and Eddie Cicotte of the Chicago White Sox, who in 1908 was nicknamed "Knuckles", are two possible creators of the pitch. Other accounts attribute the pitch's creat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laminar Flow
In fluid dynamics, laminar flow is characterized by fluid particles following smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing. At low velocities, the fluid tends to flow without lateral mixing, and adjacent layers slide past one another like playing cards. There are no cross-currents perpendicular to the direction of flow, nor eddies or swirls of fluids. In laminar flow, the motion of the particles of the fluid is very orderly with particles close to a solid surface moving in straight lines parallel to that surface. Laminar flow is a flow regime characterized by high momentum diffusion and low momentum convection. When a fluid is flowing through a closed channel such as a pipe or between two flat plates, either of two types of flow may occur depending on the velocity and viscosity of the fluid: laminar flow or turbulent flow. Laminar flow occurs at lower velocities, below a threshold at which the flow becomes turbulent. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbulence
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between those layers. Turbulence is commonly observed in everyday phenomena such as surf, fast flowing rivers, billowing storm clouds, or smoke from a chimney, and most fluid flows occurring in nature or created in engineering applications are turbulent. Turbulence is caused by excessive kinetic energy in parts of a fluid flow, which overcomes the damping effect of the fluid's viscosity. For this reason turbulence is commonly realized in low viscosity fluids. In general terms, in turbulent flow, unsteady vortices appear of many sizes which interact with each other, consequently drag due to friction effects increases. This increases the energy needed to pump fluid through a pipe. The onset of turbulence can be predicted by the dimensionless Rey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ars Technica
''Ars Technica'' is a website covering news and opinions in technology, science, politics, and society, created by Ken Fisher and Jon Stokes in 1998. It publishes news, reviews, and guides on issues such as computer hardware and software, science, technology policy, and video games. ''Ars Technica'' was privately owned until May 2008, when it was sold to Condé Nast Digital, the online division of Condé Nast Publications. Condé Nast purchased the site, along with two others, for $25 million and added it to the company's ''Wired'' Digital group, which also includes ''Wired'' and, formerly, Reddit. The staff mostly works from home and has offices in Boston, Chicago, London, New York City, and San Francisco. The operations of ''Ars Technica'' are funded primarily by advertising, and it has offered a paid subscription service since 2001. History Ken Fisher, who serves as the website's current editor-in-chief, and Jon Stokes created ''Ars Technica'' in 1998. Its purpose was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reynolds Number
In fluid mechanics, the Reynolds number () is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers flows tend to be turbulent. The turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow ( eddy currents). These eddy currents begin to churn the flow, using up energy in the process, which for liquids increases the chances of cavitation. The Reynolds number has wide applications, ranging from liquid flow in a pipe to the passage of air over an aircraft wing. It is used to predict the transition from laminar to turbulent flow and is used in the scaling of similar but different-sized flow situations, such as between an aircraft model in a wind tunnel and the full-size ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serve In Volleyball
Serve or SERVE may refer to: Sports *The act of placing a ball or other object in play in sports such as; ** Serve (pickleball) ** Serve (tennis) ** Serve (volleyball) Other * Service of process, to formally deliver legal documents * Secure Electronic Registration and Voting Experiment * SERVE Afghanistan, a UK-registered charity that works in Afghanistan See also * Server (other) * Service (other) Service may refer to: Activities * Administrative service, a required part of the workload of university faculty * Civil service, the body of employees of a government * Community service, volunteer service for the benefit of a community or a p ... * Serving (other) {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
