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

[carmelo@pacific.net.sg]

Quoting Hugh Haskell <haskellh@verizon.net>:

> That has not been my experience. I taught weight as the reading on
> the bathroom scale for several years and students seemed to get that
> without too much trouble. What they see fairly quickly is that "most
> of the time" what the bathroom scale reads is equal to, or very close
> to mg, but definitely not always, and in fact its common for that not
> to be so. When we would do the accelerating elevator experiment they
> understood quite well that their weight changed when the elevator
> accelerated, and that in that condition, although mg was still a
> force on them, there were other forces that made the scale reading
> different from mg.

Weight as the reading on the bathroom scale may not be appealing when  
it is applied on an object partially submerged. The object becomes  
"weightless" because of buoyancy.

If you prefer, the weight can still be Mg. (In this case, g is the  
centripetal acceleration due to the rotation of the Earth.) There is  
no freefall acceleration! Perhaps, Bartlett could consider this as  
apparent weight. (If I am the referee for this paper, that will be my  
recommendation!)


Best regards,
Alphonsus