Re: [Phys-l] definitions ... purely operational, or not

[carmelo@pacific.net.sg]

Quoting Hugh Haskell <haskellh@verizon.net>:

> Buoyant forces are a bit tricky, and the recent thread here has
> clearly shown. I think I would look at this from the POV that gravity
> is still acting on the object, as mg, but the support force that
> comes from the pressure differences is distributed over the surface
> of the object. That won't be measured by a bathroom scale in contact
> with the object, but it will be reflected by a lager reading on the
> bathroom scale that is supporting the water tank in which the object
> is immersed. So, I guess that I would not call the object in buoyant
> equilibrium weightless (but I'm still thinking about it).

Suppose we want to know the weight of a hot-air balloon...
When we release this balloon, Oops, it has a "free-ascend" instead of  
"free fall". Does this mean that the weight of a hot-air balloon is  
negative?

Is not this definition of weight using "free fall acceleration" still  
problematic? :-)


Best regards,
Alphonsus