ksprayberry
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Ok, I'm confused... it's a little nerve racking to be this close to the exam and have a question like this, so I'd really like to have some feedback on this if you can.
I have the Mechanical PE Sample Examination 2nd Edition, Current printing #3. Problem 53 uses standard air density of .075 lbm/ft3 to arrive at the correct solution. My first pass through, I used the specific volume off the psychrometric chart and arrived at a slightly different answer..I may have even used the ideal gas equation to derive at the density and then used that, but nevertheless, the answer I arrived at was a listed answer but was incorrect. Incorrect, but listed as a 1 of 4 choice!
So, I have an older 101 Solved Mechanical Engineering Problems book (Printing 7) and problem 9..Similar problem too, uses the method I used above...DOES NOT USE STANDARD AIR to arrive at the solution. They read 13.84 ft3/lbm off the psych chart and used that to arrive at the proper mass flow.
So which is it? Most every problem I've worked out of the Lindeberg books (Sample exam and Practice) and the NCEES sample exam all seem to use standard air to arrive at the correct answer, I will probably take this approach on the exam, but getting some feedback would be nice, you can see how this would shake your confidence quite a bit.
Thanks for your help
Kelly
I have the Mechanical PE Sample Examination 2nd Edition, Current printing #3. Problem 53 uses standard air density of .075 lbm/ft3 to arrive at the correct solution. My first pass through, I used the specific volume off the psychrometric chart and arrived at a slightly different answer..I may have even used the ideal gas equation to derive at the density and then used that, but nevertheless, the answer I arrived at was a listed answer but was incorrect. Incorrect, but listed as a 1 of 4 choice!
So, I have an older 101 Solved Mechanical Engineering Problems book (Printing 7) and problem 9..Similar problem too, uses the method I used above...DOES NOT USE STANDARD AIR to arrive at the solution. They read 13.84 ft3/lbm off the psych chart and used that to arrive at the proper mass flow.
So which is it? Most every problem I've worked out of the Lindeberg books (Sample exam and Practice) and the NCEES sample exam all seem to use standard air to arrive at the correct answer, I will probably take this approach on the exam, but getting some feedback would be nice, you can see how this would shake your confidence quite a bit.
Thanks for your help
Kelly
