Motion System Design

Sweet serves

Finagle J. Wurme is ready for the IOU varsity tennis team's spring tryouts. He trained tirelessly during the winter by lifting weights, running laps, and playing ping-pong. Now, he's eager to demonstrate his improved, powerful serve.

Finagle gets a chance to show off his new skills when he's paired with another athlete for a singles match. He steps to the baseline, tosses the ball into the air, and “Swoosh!” His racquet contacts the ball perfectly, and he delivers a solid serve like the pros.

Coincidentally, the tennis coach is also the Physics professor and will only accept players who can apply classroom material to the game. Fortunately for Wurme, it's still early in the semester: Air resistance hasn't been discussed yet and may be neglected. Assume the ball left Wurme's racquet at 20 m/sec at a 30° angle. Finagle must determine how far the ball travels during its parabolic flight before landing.

Send solutions to [email protected] by April 12, 2006. For last month's full solution and winner announcement, visit

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