"I don't know how common or not acceptence of such a definition is, but, at
least, I accept it (in a modified form). I would modify the previous
definition so that the scale in question provides 100% of the
non-graviational force acting on the body being weighed. If other
non-gravitational forces act on the body than that provided by the scale,
then, according to my definition of weight, the scale gives a faulty
reading,
rather than the weight being what that reading is. . . ."
I agree with the increased precision and care he makes to the definition,
particularly with the situation when you have one foot on the floor one on
the scale, or are grabbing the towel bar etc etc; however I part company
with respect to the !00% non-gravitational force part. In particular, I
want my fish with neutral buoyancy to be declared weightless, another way of
saying it is that I want the rock in the water to weigh less, just as we
measure it to be in the lab (hanging it from a pan balance and the rocked
immersed in the water). This would match up with the usual use of the term
"weightless" in outer space and with what goes on in the space shuttle and
also would explain why they train in huge water tanks for their
extra-vehicular activities; as they have close to the same degree of
weightlessness in the two cases, which agrees with the "bathroom scale"
definition and is not the case with strict use of David's definition.