Engineers holding PE or EIT licenses have higher average incomes than engineers who do not. To encourage registration, we present typical examination problems from registration examination preparation manuals. Readers are invited to solve the problems and submit their answers to us. From among the correct solutions we will select monthly one reader who will receive a free one-year extension to his subscription. The Virginia Engineer cannot respond to individual requests for explanations as to why answers other than those published are not also correct. Mail answers to The Virginia Engineer, 7401 Flannigan Mill Rd., Mechanicsville, VA 23111; or fax answers to 877-779-3032, or e-mail answers to The deadline for answers to this month's problem is June 10th.
The June Problem—Stoichiometry
"The supplier promises that this new coal is really, really good," the Chief Engineer tells the Plant Engineer. "By weight it's 79 percent carbon and 6 percent ash. We did a test burn in the furnace and the clinker in the pit was 90 percent ash and 10 percent carbon. What is the percent of coal burned?" "Well," the Plant Engineer replies as he punches in the numbers on his hand-held, "On a carbon basis, we ought to get . . .
(A) 89.09% (B) 91.9% (C) 98.0% (D) 99.15% (E) 99.33%
There were no correct answers
submitted for May’s problem
The May Problem—Dynamics
"You're a pretty smart fellow—try this one on for size," the Chief Engineer challenges the Plant Engineer. "Imagine that you weigh yourself in an elevator and find out that you weigh 185 pounds. The elevator starts up, and your weight jumps to 210 pounds. How fast is the elevator going up?" "Well, assuming constant acceleration," the Plant Engineer replies as he punches in the numbers on his hand-held, "I'd be going up at . . .
(A) 2.0 fpm (B) 3.1 fpm (C) 4.35 fpm
(D) 4.95 fpm (E) 5.75 fpm
The solution to last month's problem: