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joshuajune2

  • one year ago

Discussion of common physics ( must be reasonable post )

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  1. Mashy
    • one year ago
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    Ok.. i have one.. so Galileo said that when objects fall through the same height.. they take the same time to fall towards the earth regardless of what the mass is.. however.. if you consider the fact that earth is also being pulled up due to the mass.. then don't you think heavier masses would touch the ground earlier.. (ofcourse the time difference is soooo small it really doesn't matter.. but.. something to think about)

  2. ankitisphysicist
    • one year ago
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    good one..........i think all the classical laws like that of constant accelaration or gravitation as you have said are mere approximations.....i think if u go through general relativity briefly you will get your answer

  3. gleem
    • one year ago
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    Acceleration due to gravity depends only on the mass of the earth according to Newton so the acceleration is constant.

  4. ankitisphysicist
    • one year ago
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    well approximately bro

  5. gleem
    • one year ago
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    My point point was that Mashy's submission seemed fallacious given what we presuppose about the force of gravity and the meaning of force particularly in this forum. And in this forum, and correct me if I'm wrong, but isn't force still mass times acceleration, isn't action equal to reaction and isn't the gravitational force still proportional to the product of the the interacting masses? If so then isn't the acceleration of the bodies toward one another constant. So help me. In the current state of knowlege where is the approximation(s): in Newton's Second law, Newton's Third law or the Newton's law of gravity? Surely all physical descriptions are to be taken as approximations for we are merely feeling our way around our universe trying to reconcile what we "see or think we see" with how we describe the workings of the universe. We modify or discard and replace our theories as more information becomes available. Newton acknowledged his dissatisfaction with his gravitational law and Einstein brought us better understanding in his General Theory but we still are not fully sure of ourselves.

  6. ankitisphysicist
    • one year ago
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    yeah.....i agree to your point that there are physical quantities which we can only approximate. But the degree of precision matters. For you doubt, newton's equations are most elegant and practical at slow speeds. In fact, the scientists measured some contradiction in orbit of mercury in early 1900s which could not meet newton's prediction. Then general relativity came in and cleared the doubt by predicting the orbit of mercury and clearing contradiction. Also I would like to tell you that at very high speeds, i.e. speeds comparable to the speed of light, the things approximations which seem negligible at low speeds become visible. The effects are contradicting to the Newtons or galileos theory. However our common sense does not matter from the high speeds. But if you consider a particular particle or object falling into a black hole, where gravity is very intense, you would note that time almost stops and thus g=m*a does not hold. I hope your doubt is cleared..

  7. ankitisphysicist
    • one year ago
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    well at least not so straight forward. it becomes a big approximation and nothing else. HOwever, here the general relativity also does not work good enough to predict the happenings of accelaration

  8. gleem
    • one year ago
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    Ankitisphysicist, you are preaching to the choir. I know all that. My point is that this forum is primarily meant to help student of physics not confuse them. The original statement by Mashy was non-relativistic, ie classical. The statement implied that as the mass of an object in the earths gravitational field increased, the acceleration increased. (Although he covers himself by saying it is a " soooooo small" effect). It still begs the question why this would be true since any good classical student would say no there is no effect, the heavier mass will not fall faster. Since this forum is to be didactic how small is the effect, or how big does the mass have to be to cause a measurable effect.?

  9. ankitisphysicist
    • one year ago
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    thnx 4 explanation. As to account for that reason the effect discussed by @Mashy gets considerable when the ratio of freely falling object and the earth gets smaller. For example we can imagine the sun and the moon. If the earth had been close to sun alongwith moon, this effect gets considerable as the distance (r) is same for moon and earth. But Earth falls faster than moon into the sun even if there is vacuum out there in the space. I would request correction if I am wrong anywhere. @gleem ((classical view ))

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