# NCEES 2008 # 509 Thermal and Fluids - Arithmetic not computin



## abourne (Oct 26, 2010)

I'm calculating this out over and over again and NOT getting anything close to the answer:

76,900 BTU/hr

A = 31.42 ft^2 = (Pi)(D)(L)

Q = h(A)(T_s - T_a) + (Sigma)(A)(e)[(T_s + 460)^4 - (T_a + 460)^4]

Q = (5)(31.42)(450-65) + (0.1714(10)^-3)(31.42)(0.5)(910^4 - 525^4)

I've calculated the above about a billion times and I'm not getting anything close to 76,900 or 77,000

I've done this on my calculator and a spreadsheet.

Is anyone else having this problem?

If not, what could I possibly doing wrong that this isn't computing?


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## abourne (Oct 26, 2010)

SOB

It's an error with Sigma:

Just found the Errata

Sigma is

0.1714(10)^-8

NOT

0.1714(10)^-3


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