## Realtimephsics 2 years ago Is anyone here familiar with Cavendish experiment? or Newton's gravitational Law?

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1. Mashy

yea..

2. telltoamit

3. Realtimephsics

Thank you very much for the historical presentation. I have trobule with this experiment. Cavendish experiment design is not measuring Earth's density but measuring air density. G published values in past few decades have changed from 6.672 x 10@ -11 to latest value of G = 6.67384 x 10^ -11 is a measurement of air density. To start with you have two meatl balls not in touch with Earth but in touch with air. Newton's equation is F = G mM/(r.r): G uints is 1/d (t.t); d = density and t = time; G = 1/(4pi/3)(2/5)d (t.t); volume factor of air (4pi/3); spherical moment of inertia used in the experiment (2/5); t = sidreal time; d = air density = 1.2041km/(m.m.m)

4. Realtimephsics

I took Cavedndish experiment and had it inside a glass chamber and sucked air out and gravity vanished. It is alson very well known that gravity is reduced with altitude where Earth's mass and density is not lower but air density and mass is lower

5. Vincent-Lyon.Fr

Quote : "I took Cavedndish experiment and had it inside a glass chamber and sucked air out and gravity vanished" WHAAAAT???? Gravity vanished!?!

6. Phloyd

oh i would love to chime in here .. but i know my argument would confuse the issue ...as far as the Cavedndish experriment one could argue that the lack of conductive material , the aloted space in the vaccume would allow for the apperance of lack of gravity ( * NOTE * i argure that G is actualy a extencion of EM not a force unto itself ...this is UNPROVEN .... but makes more sence ) and as far as altitude and the weeking effect of gravity ....one could argue that the further you are from a EM pull / effect the weeker it is on the opposing object ......( again * NOTE * this is just my point of view do not try to argue this in class as it WILL be counter productive )

7. Mashy

phloyd.. don't put your view here.. lets discuss your gravity view only that other thread you opened :D... lets not confuse the poor chap :D.. but i can prove you you are wrong though!

8. Phloyd

i put in my disclaimer ( *NOTE *) ...lol

9. Mashy

:P..

10. CreAtivSpelErr

@Realtimephysics. Gravity and air pressure are completely unrelated. If vacuums made gravity disappear then planets wouldn't be held in orbit in space. Gravity and air resistance are both forces, and as such, they can each separately contribute to the motion of a falling object but as for Cavendish, he was measuring two masses, the distance between them, and the force of gravity (technically, the force of the torsion spring at a point when it was in equilibrium with the force of gravity) - with those measurements G is the only unknown left in Newton's law of universal gravitation. He wasn't interacting with the air or the earth, the interaction was strictly between the lead spheres.