Cool example of gravity
- Thread starter seth gecko
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u can do this at home
put a leaf on a book
drop the book
because the book blocks the air friction the leaf falls at the same rate as the book
indeed, because friction is slowing down the book, the book is in the leafs way!
Galileo realized, that the speed of a falling body is independent of its weight. He argued as follows: suppose that the manner in which a body falls does depend on it weight, then a two pound rock should fall faster than a one pound rock. But if we take a two pound rock, split it in half and join the halves by a light string then on the one hand this contraption should fall as fast as a two pound rock, but on the other hand it should fall as fast as a one-pound rock .This argument shows that the Aristotle's assumption that the speed of falling bodies is determined by their weight is wrong.
This result is peculiar to gravity, other forces do not beahve like this at all. For example, if you kick two objects (thus applying a force to them) the heavier one will move more slowly than the lighter one. In contrast, objects being affected by gravity (and starting with the same speed) will have the same speed at all times. This unique property of gravity was one of the motivations for Einstein's general theory of relativity .
i do not understand what he said about einstein
einstein says falling bodies do not fall but stand still
he reasoned that if the background was taken away you could not tell if the objects were falling therefore they were not falling at all so all objects " fall "at the same speed because they are not falling ??!!
can someone explain this nonsense ?
just because you cannot see the fall because the background is taken away therefore you have nothing to compare the fall to does not mean they are not falling
that is like saying a spaceship would not be moving if there was no matter to compare its speed to
put a leaf on a book
drop the book
because the book blocks the air friction the leaf falls at the same rate as the book
indeed, because friction is slowing down the book, the book is in the leafs way!
Galileo realized, that the speed of a falling body is independent of its weight. He argued as follows: suppose that the manner in which a body falls does depend on it weight, then a two pound rock should fall faster than a one pound rock. But if we take a two pound rock, split it in half and join the halves by a light string then on the one hand this contraption should fall as fast as a two pound rock, but on the other hand it should fall as fast as a one-pound rock .This argument shows that the Aristotle's assumption that the speed of falling bodies is determined by their weight is wrong.
This result is peculiar to gravity, other forces do not beahve like this at all. For example, if you kick two objects (thus applying a force to them) the heavier one will move more slowly than the lighter one. In contrast, objects being affected by gravity (and starting with the same speed) will have the same speed at all times. This unique property of gravity was one of the motivations for Einstein's general theory of relativity .
i do not understand what he said about einstein
einstein says falling bodies do not fall but stand still
he reasoned that if the background was taken away you could not tell if the objects were falling therefore they were not falling at all so all objects " fall "at the same speed because they are not falling ??!!
can someone explain this nonsense ?
just because you cannot see the fall because the background is taken away therefore you have nothing to compare the fall to does not mean they are not falling
that is like saying a spaceship would not be moving if there was no matter to compare its speed to
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I believe they meant, that both objects were attracted to the gravite at the same rate no matter of weight. And without friction.
no
go to 3.55
he clearly states einstein thinks there is no force acting upon a falling body therefore they are not falling which is why falling objects appear to be inconsistent with other forces ( ie kick two objects and the lighter one goes further) because they are not falling
It sounded like there is more to the video, since it seemed to stop in mid-thought.
Maybe it means it depends on your frame of reference. If you stood in the vacuum chamber on the top of the beam, were blindfolded, and jumped, you would feel weightless. You could debate if you are moving towards the floor, or the floor is moving towards you.
They are travelling along a straight line in spacetime, which is curved by gravity, under pure inertia with no force acting on them. This is a consequence of relativity, where you can take any object in space and use it as the frame of reference for the rest of the universe.
Glad everyone enjoyed the video. Hard to believe its not CGI.
I was doing a google search for "extra large penis vacuum pump" (strictly research!) and voila, I found this video.
Here's what Cox says towards the end, referencing Einstein, that has Yoga Face questioning:
BTW: does anyone know where, hypothetically speaking, one could get an extra large penis vacuum pump??
I was doing a google search for "extra large penis vacuum pump" (strictly research!) and voila, I found this video.
Here's what Cox says towards the end, referencing Einstein, that has Yoga Face questioning:
The explanation is actually fairly simple - Cox didn't clearly identify which Einstein thought this up.....he could have been referencing comedic genius Bob Einstein, or even Albert Lawrence Einstein (aka Albert Brooks, another comedic genius). We assumed that it's physics genius Albert Einstein. In other words, our perception is influenced by our reference point, and thus, without a point of reference, differentiation would be imperceptible Without a background as a reference point, the perception of movement doesn't exist. The ball & feathers may not be moving as everything around them is moving relative to them. If I remember correctly, and I probably don't, the example used was a rocketship accelerating away from earth - to occupants in the ship looking out a window, it would appear earth is "falling" away from them. Like Albert L. Brooks & Bob Einstein, its all relative.
BTW: does anyone know where, hypothetically speaking, one could get an extra large penis vacuum pump??
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Einstein's aware that 'falling' is a relative concept. No one standing on the earth has any means of proving the Earth—and the buildings and apparatus attached to it—didn't move towards the ball and feathers until they collided. Nor can they prove that anything concerned was ever stationary and at rest.
But it certainly is convenient to 'observe' a gravitational force to soothe the brain-pain of trying to account for all that relative motion.
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Here's another cool video that should tie everything mentioned in this thread together very neatly - gravity, Einstein, falling bodies, etc.
I present to you: Super Dave Osborne (aka Bob Einstein) falling off the CN Tower!!!
I present to you: Super Dave Osborne (aka Bob Einstein) falling off the CN Tower!!!
Imagine that! A camera underwater gets the same sort of pix in zero G, as on Earth! Proves pixels have no mass I guess. And something mebbe about surface tension.
I think Newton would beg to differ. There is a force between the two objects that is identical. When force is applied to an object, it will accelerate at a rate proportional to it's mass. With the same force applied to the 1/2 pound ball and the 12,958,069,340,000,000,000,000 pound earth; it is obvious that the ball wasn't standing still as the 12,958,069,340,000,000,000,000 pound earth accelerated toward the ball (and with the inertia gained, didn't continue to careen out of the solar system).
Perspective is relative but we can prove mathematically that the earth didn't move towards the ball.
But you have just said—according to pre-Einsteinian concepts—that there is an identical force acting on both Earth and objects, therefore there must have been some movement of the Earth resulting from that force, albeit an infinitesimally small movement. Even Isaac—and my old Physics teacher—said so, before saying we could ignore it for practical purposes.
Albert however could not, as he was trying to figure how The Rules applied to 'objects' that had neither mass nor size (for all practical purposes) but still did really significant stuff in their own teensy universe as well as in 'our' bigger one. Since at that time we were using those 'universal' rules to 'blow stuff up real good' it really mattered. If that sort of universal rule meant that no one standing on the Earth could prove by observation that it hadn't moved at all, nor been all that moved, so be it. But he certainly wasn't the first to know that it had moved.
I do like your image of Our Mighty Planet sent careening through the galaxy by falling feathers though! Beats butterfies in Brazil all to hell and gone for Chaos Theory illustration.
Are you moving right now? Probably you would say no but in fact you are on the surface of the earth that is rotating making you go at something like 400 m/s, revolving around the sun at around 30,000 m/s, our solar system revolving around the galaxy at 222,000 m/s and our galaxy is moving at some other ridiculous speed.
Simply put, movement is relative to how you observe it.
Put in a more simplistic example, if you are sitting still in your car you are also moving at the same speed as your car.
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