Motion System Design

Feelin' the heat

It's a warm, sunny Saturday afternoon and another academic year has officially come to a close at IOU University. Finagle J. Wurme is celebrating by inviting his Thermodynamics class over for a barbeque.

The picnic tables are out, covered with red and white checkered tablecloths. His guests of honor, Prof. Joule and Mr. Kelvin, the T.A., have just arrived carrying a strawberry cream pie and Jello for dessert. Classmates are also bringing food: Jovial Jamie is making potato salad; Grillin' George is preparing hamburgers, hotdogs, and chicken; and Chef Wurme is cooking his favorite — corn-on-the-cob.

Wurme is expecting nearly 30 people, and he needs to prepare a lot of corn quickly. So he borrows his grandmother's 2.5 kg aluminum pot. He turns the burner up to 125°C and pours 0.2 kg of water at a temperature of 30°C into the pot. However, Wurme gets distracted greeting his guests, forgets to turn the burner up higher, and therefore, only boils part of the water. If the final temperature of both the pot and water is 95°C, what fraction of water changes to the gaseous state?

Send solutions to [email protected] by August 16, 2006.

Win a spectrum analyzer

The winner of this month's problem receives a 2.4 GHz spectrum analyzer — the Wi-Spy — from MetaGeek LLC, Boise, Idaho. It tracks and records wave frequencies that can interfere with a wireless network. For additional information, call (208) 284-4080 or visit

2.4 GHz Spectrum Analyzer Features

  • Troubleshoots interference from Wi-Fi (802.11 b/g/n), microwave ovens, cordless phones, and Bluetooth

  • Wi-Spy software displays many wave types, stores real-time data, and analyzes current, average, and maximum signal strengths

  • Runs on Windows, Linux, and Mac operating systems

  • USB key device is about the size of a small flash drive

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