MathCad (2001i Pro) defines lbf (pound force) as 32.174 mass * length / time**2. Since we all recognize this as acceleration due to gravity we know the units are lbm, ft, and seconds squared. But the textbook definition of lbf is the above divided by the "gravitational constant" also 32.174 but the units include lbf in the denominator. This is critical; it shows that on earth, lbf and lbm are equivalent. But MathCad doesn't see it that way and it has been playing havoc with some gas calculations I'm doing. Any comments?
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