Question

Cheater knowing Fluid Dynamics? - Red Sox ace Jon Lester pitched against the St. Louis Cardinals in Game 1 of the 2013 World Series, scattering five hits while striking out eight players over 7.2 scoreless innings en route to an 8-1 Boston win for an early 1-0 series lead. But people noticed that he constantly rubbed the ball against the inside of his glove, maybe with resin or some other gel? Or trying to roughen the ball with a tiny piece of sand paper? If this were true, the following was what he had actually achieved in terms of fluid dynamics, EXCEPT: a. A ball with gel to make it smooth will create less surface shear stress and thus less drag. b. A roughened ball would make the flow's boundary layer undergo an earlier transition from laminar BL to turbulent BL, so that BL separation was delayed and thus a reduced drag - a faster pitch! The drag characteristics of the ball would change drastically with the gel, and so would the ball path - making it harder to hit. d. Vaseline on the ball could make the dirt particles stay while travelling - making it a “rough ball." c.

Answer 1

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Cheater knowing Fluid Dynamics? - Red Sox ace Jon Lester pitched against the St. Louis Cardinals in Game 1 of the 2013 World Series, scattering five hits while striking out eight players over 7.2 scoreless innings en route to an 8-1 Boston win for an early 1-0 series lead. But people noticed that he constantly rubbed the ball against the inside of his glove, maybe with resin or some other gel? Or trying to roughen the ball with a tiny piece of sand paper? If this were true, the following was what he had actually achieved in terms of fluid dynamics, EXCEPT: a. A ball with gel to make it smooth will create less surface shear stress and thus less drag. A roughened ball would make the flow's boundary layer undergo an earlier transition from laminar BL to turbulent BL, so that BL separation was delayed and thus a reduced drag - a faster pitch! The drag characteristics of the ball would change drastically with the gel, and so would the ball path - making it harder to hit. d. Vaseline on the ball could make the dirt particles stay while travelling - making it a “rough ball.” c.