Bend it like Roberto Carlos!
Beckham does not even come close.
Ever wondered about Roberto Carlos and his wicked free kicks? Where does he get it from? The ball has gone past, bent away from the wall of defenders jumping mortal inches off the ground clutching their goolies in an absurdly self indulgent gesture. The ball is on its way to Alpha Centauri on booster rockets overcoming the G force in the stratosphere. Just when Joe Miller sitting in NASA, Houston is whooping it up, high fiving his team mates having identified the object as an asteroid, calling it Millie 58 after his estranged wife (The number refers to her age. Not nice, Joe!!); the ball stops on a dime and swoops down bending towards earth, like a hawk spotting its prey. The goalie who has given up and has already called his resignation through satellite phone conceding 25 goals to this Brazilian side, sees this gnat coming through his peripheral vision. It's a gnat; it's a bumble bee; it's a soccer ball; it's a GOAL!! I shall flail my arms uselessly and pretend that I care.
What Roberto Carlos does with that extraordinary sideways bend of that ball is described as the Magnus effect by projectile physics eggheads. The spinning projectile be it a soccer or cricket ball creates a different airflow speed on both sides of the ball. As the ball spins around its vertical axis, the air perpendicular to its spinning side flows faster, e.g., a counterclockwise spin. The air opposite the side of the spin flows slower. An imbalance of forces is created, causing the ball to bend. Techies delight in calling this phenomenon, Bernouillis principle. In Washington politics, spinmeisters use this principle to bend reality.
To impart this type of spin one has to kick the ball away from its center of gravity. But the key is not just gravity; its levity. The ball has to be kicked hard enough to clear the wall of defenders away and up. This to minimize what are known as the drag forces. We are familiar with these forces, wakening to them every Monday morning. To lessen the drag we ingest caffeine and sugar. This to create a tumult in the system. The more tumult; less the drag. In the exact way, if the ball is kicked hard enough, it creates a turbulence in the airflow, lessening the drag forces. The ball speeds up. It catches a thermal. The wall of defenders jump up as the ball whizzes past. Goombye! Did I say that they clutch their goolies in a futile gesture??
But to bend the ball, it needs to slow down appreciably and this happens because the airflow becomes smooth or laminar. The drag forces increase and the ball bends. At a point in time and space, sometime soon after the ball deviates away from the defenders, it slows down and bends back in towards goal. The slower the ball, the greater the width of the bend. This is the equivalent of your officemates saying, "Chill dude, you flyin' high." As the caffeine wears off, the more amenable you become to reason. People make plans that include you. Social ones.
Roberto Carlos does not know these physics in the declarative sense. But he is a superb athlete. And all superb athletes are procedural physicists. Which gives rise to this question. Why aren't more physicists, soccer players? Well, there is more to soccer than the free kick. And when the Brazilians play, you have to go Whoa!!! And not Why??