Re: No free lunch

nospamplease wrote:
I think you're still having a problem with the
concept of mass. An important concept if you're
trying to build stuff like cars, airplanes,
spaceship. Here on earth, the amount of air an
object displaces also affects an objects weight.

Actually, no it does not.
weight = mass
It has since the standard for weight was changed
long ago when people found out they were getting
ripped off by a variable scale standard.


There's a good reason a lot of stuff is sold by
mass (kg) not weight (lbs).

No there is no real reason left.
The standard was changed a good bit of time ago.


The gravitational
force (lbs or Newtons) between objects varies
inversely as the square of their distance.

That is force,
not weight.


But
their mass (Kg, Stone, Slug) doesn't change.

Neither does the weight, again you are using an old
definition of weight that was dropped for a new
and correct industry standard.
Until you realize this, you will not grasp this
almost but not really free lunch.
Not one person has come up with
the real fact that it is not a free lunch at all.
but I am waiting to see if anyone can.
:)

When
your 100lb cube is floating, by definition it is
weightless (0 lbs)

Nope,
it has added 100 lbs to the container holding the water.
the entire container gained 100 lbs.

.Half its volume is submerged,
all of its mass is being displaced (45kg or 45
Liters of water). Also true that all of it's
weight is being displaced (if you measure its
weight near the water).

No,
all it's weight is added to the total wight of water
and the mass you placed in it.


Flotation isn't the best
way to demonstrate the concept of mass. But the
energy of an object in motion is a function of its
mass, not its weight or volume. If you don't think
this is an important distinction, try making your
millions selling helium balloons by the pound.

You really need to find out "weight" is not what you
think it is anymore.
:)

--
James M Driscoll Jr
Spaceman



.

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