Posted: 11:1a.m. IST, August 12, 2012
Washington, August 12 (ANI): Table tennis players wield their paddles with an intuitive command of the forces of nature - with Newton at their sides, skilled athletes can force a ball to dip, spin and hop in a constantly shifting strategic game of deception, power, and accuracy, a new study has revealed.
Curve balls may help a pitcher strike out batters in baseball and some nasty spin can make an opponent sweat to return a tennis serve.
However, more so than in any other ball game, in table tennis - where the ball is so light and so small -dedicated players must master the physics of spin.
While [the spin] strategy is also employed in baseball, tennis, cricket, and sometimes soccer, it absolutely dominates the game of ping-pong, David R. Dowling, professor of mechanical engineering at the University of Michigan in Ann Arbor, said.
A straight-up fire-throwin' fast ball pitcher may be successful in baseball. However, the equivalent table tennis player, who does not use spin to make the ball's trajectory curve, may easily be defeated by a table tennis player who does use spin, he said.
The reason spin is such a dominating force in ping-pong can be seen when you consider that the ball is actually travelling through a fluid, in this case air.
In physics terms, when a ball travels without spin, the air moves over the top, bottom, and sides at the same speed and the pressure forces are balanced.
However, when a ping-pong ball spins as it travels through the air, these pressure forces become imbalanced, causing the ball to veer off to the side or move higher or lower as it flies. Ping-pong players use these imbalanced forces to control a ball's path.
The phenomenon, which fluid dynamicists call the Magnus effect, can send a ping-pong ball curving up, down, left, or right - always at a right angle to the direction of motion - depending on which way the ball is spun.
Fluid dynamics' importance for the sport becomes clearer at high altitudes, where there are fewer air particles for a ball to collide with.
Here, the thinner atmosphere reduces an object's air resistance and weakens the Magnus effect, causing a ball with top spin to travel farther than it would at sea level, says environmental fluid mechanics expert Jorge Escobar, an assistant professor at Javeriana University in Bogota, Colombia, and a competing table tennis player for 15 years.
In his city, 9,000 feet (2,745 meters) above sea level, even experienced players might find their returns flying far beyond the edge of the table, Escobar says.
Play depends on more than the density of air; the shape and weight of the ball, as well as the distance it has to travel, also affect how much control a player can exert.
A larger or heavier ball could travel the relatively short field of play of a ping-pong table without much spin-induced trickery, but the smaller and lighter table tennis ball is at the mercy of the Magnus effect - and inexperienced players are at the mercy of opponents who can skilfully exploit it.
The study has been published in American Physical Society's Division of Fluid Dynamics. (ANI)