Consider an array of vertical rectangular fins, which is to be used to cool an electronic device mounted in quiescent, atmospheric air at T 27C. Each fin has L 20 mm and H 150 mm and operates at an approximately uniform temperature of Ts 77C. (a) Viewing each fin surface as a vertical plate in an infinite, quiescent medium, briefly describe why there exists an optimum fin spacing S. Using Figure 9.4, estimate the optimum value of S for the prescribed conditions. (b) For the optimum value of S and a fin thickness of t 1.5 mm, estimate the rate of heat transfer from the fins for an array of width W 355 mm

ENGR 3341 Probability Theory and Statistics Prof. Gelb Week 2 homework solutions Textbook problems: Section 1.5: Problem 25: A professor thinks students who live on campus are more likely to get As in the probability course. To check this theory, the professor combines the data from the past few years: 1. 600 students have taken the course. 2. 120 students have got As. 3. 200 students lived on campus. 4. 80 students lived off campus and got As. Does this data suggest that “getting an A” and “living on campus” are dependent or independent Solution: let C be the event that a random student lives on campus and A be the event that he/she gets an A. We have: 120