What about putting the mailbox on a pivot, with a heavy counterweight at the base? Let gravity stand it up, but give it a range of movement.
"Forget pounds and ounces, I'm figuring displacement!"
If we accept that: MBG(+)FGSF(=)HBG(F1)
And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1)
Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT?
PB answer: It depends.
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