TFS · Practice Exam 2 · Problem 7PDFSolution in PDF ↓
TFS · Practice Exam 2 · Problem 7
Problem & Solution
Video Synthesis
- Problem: A fan delivers 10,000 CFM of 70 degree air at sea level.
- Key values: 14 %, 4 %
- Reference: reference handbook
- Result: And that gives us a new volume flow rate at 4,000 feet of 11,000 and 97 CFM, which is closest to answer choice C.
- ✅ Answer: C
Office Hours
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Student questions asked in live office hours about this problem
OH 81
Q: I used a formula from Practice Exam 1 Problem 8 (relating volume flow rates to pressures and temperatures for a compressor) to solve this fan problem and got the right answer—is this method acceptable?
A: Yes, it's totally valid and shows good intuition since fans and compressors are conceptually similar fluid machines. That said, also make sure you can use the density factors from the reference table as an alternative approach—try both methods to verify they reconcile.