Whipping his racquet through the air like a cesta in jai alai, Rafael Nadal produces such tremendous topspin that the ball sometimes seems to catapult off the court, creating a shot as challenging to ...

Equipment: A tennis ball on a string. What it does: Swing the ball on the string to show circular motion. Release the ball to show the instantaneous velocity of the ball. Concepts Demonstrated: ...

Red ball, white ball, pink ball, no ball, Kookaburra ball, Duke ball, seaming ball, reverse-swinging ball, spinning ball, old ball, new ball, hard ball, soft ball... With so much tacit language in ...

Available at: Home Depot, Sears, Home Hardware, Amazon.ca Price: $24 for single beams up to $50 for double beams. Dangling a golf ball on a string in the garage is the best low-tech way to know if the ...