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Motion System Design


Coco the raccoon could not go on. Ever since the town where he lived had made everyone switch to refuse cans, the bags of garbage he so easily used to rip open were no longer available. So Coco sulked along, blind to the fact that he was crossing a busy street.

Just then, Ron DiMova was driving home from a long day at the office, taking it easy and coming down the street at 20 mph — partly to enjoy the Spring scenery and partly to avoid getting a speed-trap ticket at the end of the road's 12° decline. Suddenly, he sees a very moody raccoon moping across the street. If Ron slams on his brakes, how far away must Coco be to avoid certain doom? Assume the kinetic friction coefficient between the wheels and road is 0.6 and that the car weighs 3,000 lb.

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

Win a USB digital I/O device

The winner of this month's problem receives a portable NI USB 6501 device from National Instruments Corp., Austin, Tex. It provides reliable data acquisition and control, and with plug-and-play connectivity, suits home, academic, laboratory, and industrial applications. For additional information, call (800) 531-5066 or visit

USB 6501 Features

  • 24 digital I/O lines, one 32-bit counter
  • Over-voltage protection, 8.5 mA current drive
  • USB 2.0 full-speed (12Mbit/sec) bus interface; OEM version available
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