I can't understand your reply.
In Mathcad, .
If I am wrong, you mean Valely also wrong. He also shows center weight is 30 gm.
This is the answer of nature.
My Mathcad Prime says:
and
if I use it correctly.
I know that g is a unit of mass, being 1 kg/1000, it is defined like that in ISO 80000-1.
The prefix k means 1000, so 1/1000 part of 1 kg gives you 1 g.
The Earth's gravitation at sea level is (defined at?) 9.80665 m/s^2, the symbol g is often used for that value.
Note that there is a difference between g and g.
The unit of length is m and 1 km is 1000 m.
According to common rules Nm is often used as a unit of torque: N*m. Likewise gm can be understood as g*m, that's not a unit of mass, and not a unit of force.
Using gm instead of g as a unit of mass should be avoided.
Luc
Luc is taking advantage of Prime's confusing habit of allowing a constant (the g in gravity, the left example), a unit (the g defined as kg/1000,) and several other types:
This "feature" has caused a lot of pain and confusion . . (IMHO!)
I'll save you the trouble of firing up Acrobat or another PDF reader.
Here's the picture of the contents:
Luc
Here's the experiment for the left side.
I took the same beaker and the same kitchen weigher.
Then I grabbed the blue ball that floats in my garden pond, a small plastic bag and a circular and a strong magnet (I don't want to glue something inside the beaker, I decided to let two magnets hold the bag with the ball under water)...
In short: this stuff:
I poured water in the beaker, dropped all the stuff on the weigher and set it to 0.
Then I put the strong magnet inside the plasic bag (with the ball) and drowned it. The magnets keep each other together, keeping the ball and plastic bag fully under water. I expected no difference in weight and got this:
No difference in weight, as expected. Now my weight scale isn't capable of weighing the amount of air entrapped inside the ball (and there's still some in the plastic bag). I expect however that even if I could measure that, I would see no difference because, per my former reasoning: air remains suspended in air (instead of dropping on the floor or floating to the ceiling).
This leads me to the conclusion that the left side weight is that of only the water, that is:
Luc
A very nicely designed experiment! But I have one objection (and one suggestion.)
The objection (more an observation):
With the ball floating on top of the water the ball is partially submerged; this raises the water level (see Val's note.) Better to weigh the ball outside the beaker.
And the suggestion: substitute a block of wood for the ball of air. The block should be big enough that the scale can recognize it. We should be able to see any difference submerging it causes.
Kudos for this:
"One measurement is worth a thousand expert opinions."
Igor Sikorsky
My last puzzle of this topic is that why we have no advice from Werner_E, the No.1 specialist of Mathcad community.
You will laugh, but the weight of one kilogram of iron is more than the weight of one kilogram of wood.
Weight is the force with which an object acts on the scale.
Gravity is mass times the acceleration of gravity.
