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Old 07-31-2019, 12:28 PM
HuntingRoss HuntingRoss is offline
Senior Member
Join Date: Sep 2014
Posts: 271
Moving forward to where ?

Hello Ramset

I'm not certain where all of this is going and I'm not seeing any questions that need addressing.

My only comment / observation :

A 1kg mass sitting in a plane flying in the same direction around the earth as a 1kg mass in orbit do not weigh the same. The plane is slow and the wing lift exerts an equal and opposite force on the mass. The orbiting mass is fast to the point where it's not slow enough to drop to Earth and not fast enough to be thrown out to space, it is therefore considered to be constantly falling. The centrifugal / centripetal forces cancel. The same mass in space would have weight unless it is so far distant from the attractive mass that it is considered weightless. I think in your comment "What you can say is that the 1Kg has a weight of 9.8N but exerts a force of 0N on it's surroundings" you are resolving the two definitions of weight. Fair enough.

"In the absence of air's buoyancy force a litre would not weigh 1 Kg if it was originally defined immersed in air". A litre of water does not weigh 1kg and I haven't seen a definition for the weight of water and the conditions under which it was measured where the buoyancy effect should/would have been considered.

I'm assuming this path of enlightenment is leading to a bigger question or point from your title "a build is moving forward" ?

Good hunting
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