Is it possible that the gravity that keeps our feet planted on the Earth is..

both

 

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This is high school physics not a mystery.

Gravity on earth results in an acceleration of 9.8 m/s^2 towards the center of the earth. That result in a downwarad force that in my case is about 180 lbs. As you have probably noticed we are not in the center of the earth. The reason I do not move to the center of the earth there must be a force that equals my 180 lb force in the opposite direction, that is the normal force. Where does this mysterious force come from? When I stand on a piece of steel for instance my weight causes the steel to slightly compress by deforming the molecular bonds, the resistance to the deformation of the bonds is a force agains my feet. The steel or whatever material will compress until it matches the force pushing against it. If the force is too much for the material the material will break.

The normal force is not just about gravity. Push against a wall. In other words put a force against the wall. Do you go through the wall? If not then the wall must be pushing against you at the same force as you are pushing against the wall, this is the normal force. Suspend a board between 2 saw horses, put a wieght on a board and the board will bend a certain amount. The weight does not move after the initial deflection because the board is developing a normal force in the opposite direction of the force of gravity. The stressed bonds can easily be seen by the deflection of the board. Increase the weight on the board and the board will deflect farther until the normal force equals the weight.

 

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I know all of this already. I didn't even need high school physics to figure that out. I'm talking about how the Earth movies relative to an object on its surface can create a normal force. The only problem is that you see the Earth's rotation as the same as having your body on the end of a string being swung around. If you remove the idea that there is a centripetal force, it all makes sense. I can't seem to get you to imagine that very well though. The Earth may rotate very fast, but it takes a whole day to do one rotation. That's only about 0.035m/s^2 of acceleration IF there is a centripetal force. Wouldn't you think that you would have enough inertia to keep you from flying off into space from that? Don't forget that nothing on earth is 100% rigid. An inelastic collision isn't going to send anything flying off into space. We also have this nice atmosphere that makes it extra difficult for things to just fly away. Imagine if you had a fuzzy tennis ball in space and you could make it move like the earth. Then imagine grains of sand floating about in an enormous cloud that the tennis ball passes through. The tennis ball would end up covered in sand and it wouldn't fly away. You wouldn't really even need a fuzzy tennis ball, you could use a racket ball instead and the same thing would happen. The ball would collide with the sand in its path and the inertia of the sand and the ball would cause them to "press" together. There's nothing pulling it back off, so it doesn't fall off the back side and it has momentum with the ball now anyway, so it would stay with it. The ball even moves in such a way that even if a grain of sand were thrown from the surface that it would still collide with it again unless it was thrown very far from it.

That is the way I see the Earth relative to objects on its surface. I don't see how that is wrong if there were no mass attraction.

 

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When you throw something "up" in the air, all of the acceleration happens before the ball leaves your hand. From that point on, what you witness as the ball "going" up in the air is the ball moving slower than the Earth in the opposite direction you threw it. However, the ball is NOT moving any slower in the direction perpendicular to your throw and the Earth isn't moving in a straight line away from the direction you threw it, so the ball collides with the Earth again. It collides in roughly the same spot it was thrown from because it still has the same speed as that spot in all directions except "up". Actually, the ball has a greater speed in one of those directions because you're actually throwing the ball in a diagonal vector away from the surface which is not completely against any of the major directions the Earth is moving in. The ball will come back down even without gravity.

 

I am presuming that you accept the fact that that would happen on all places on the Earth's surface - so even if everyone on the planet threw a ball upwards at the same time they would all see the same behavior (i.e. a return to Earth.)

Given that, how can the Earth be moving towards all the balls that are in the air at the same time? Do you claim the Earth is constantly expanding to "catch up" with the ball?

 

Because depending upon where you are on the surface, you can only throw the ball "up" in a direction that is away from the center. More importantly, the directions that ball has momentum in before you throw it are a bit different and the Earth moves relative to that point on the surface differently. "Up" is relative to where you are, it is "down" on the other side of the Earth. This is why doesn't matter where you're standing on the surface when you throw a ball "up". If you don't believe me, then maybe if you do the math you will see. It seems like very difficult math because not only is the ball moving, but so is the Earth, so you actually need a separate point of reference, which we don't seem to have unless we imagine a fixed 3D universal grid coordinate system. I need help with the math, so I haven't done it myself.

 

Correct. And thus the Earth must be moving away from its own center, in all directions, constantly, for your claim that "the Earth moves to meet the ball" to be valid. No amount of mathematical jiggering will allow you to avoid that basic principle.

Correct. So the balls on the "down" side of the planet would go flying away.

 

The Earth doesn't just move to meet the ball, the ball also moves to meet the Earth. Have you even looked at a model of the Earth since you started contributing to this thread? Did you download the Celestia app? It doesn't matter where you throw it from, the Earth does not move in exactly the opposite direction on the same vector of your throw.

No no no. Why would they go flying away? They have momentum to stay with the Earth. Do things go flying out of your hand when you're traveling at a steady speed in a car? NO. If you toss a ball up in moving car, does it come right back down? YES. It doesn't drop on the ground way back where you were when you threw it up.

When you throw a ball in the air, the place you threw it from is not in the same place when it comes back down. If you were on the equator and it takes 1 second to go up and back down, the point has moved 0.465km from that point on the surface relative to the center of the Earth, 29.7km from that point relative to the Sun and ~225km relative to the center of the galaxy.

 

jiveabillion you are really and truly not making any logical sense. It is not that we do not understand what you are saying - it is that we can not believe you are saying it because it is complete illogical nonsense. There is no need for me to reply since your mind seems to be made up and no amount of counter evidence seems to make any difference. I will check back in after your talk with the physicist. I fear you will simply believe that he can't understand you either when he tells you your ideas are wrong.

 

If I could use a dictionary to falsify his physical claims...

You know this guy isn't even trying to make sense.

 

if that were the case the rotation of the earth would throw us off the planet like rain drops on a spinning basketball

 

Spin a basket ball 1 round per day or 0.000696rpm. Do the drops fly off? Nope. They'd evaporate first.

 

Maybe if you think of when you throw an object, you're just deflecting it.

 

It's impossible that either tensors or fields to make sense to you in light of what you've already said. Further, even if you did understand it, it completely contradicts what you've said here.

We don't need anything more than general relativity to explain gravity (as it applies here) certainly not the random ideas you have offered. None of them have anything to do with the causes of gravity.

In general relativity "the movement of the earth" is not in Euclidean space. You are giving us nutty "causes" which are all in Euclidean space (your vector calculations for example). You can't get there from here.

That's absurd.

Not quite. However that statement proves that you aren't sure what the term means. The pendulum us simply a device that responds to both gravity and the rotation of Earth.

If what you were saying were even remotely true, then a person's weight at the poles would be substantially different at the equator which of course is not correct.

According to your beliefs, there is no interaction between a body above its surface. Therefore this whole premise contradicts your main idea.

If that were even remotely true all of orbital mechanics would have been wrong, Newton would be unknown, and you would be basking in the praise heaped on Newton, for having finally explained these strange orbits, which would be entirely different than the ones that actually occur.

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Why? Basic Netwonian mechanics says that once something is in motion it tends to stay in motion (same direction, same speed) unless another force acts on it. So if you throw it away from the Earth it keeps moving away from the Earth unless another force acts on it. What is the other force?

Yes.

Right. For your system to work the Earth would have to move in roughly the same vector of your throw. It does not.

No, you have just given it momentum away from Earth by throwing it.

Correct. They stay there, due to the product of friction and the normal force provided by gravity. Remove gravity and the object would slowly float away since the Earth spins. Of course the car would float away too, so you'd have to postulate a car on rails or something. The only way to avoid this would be to drive the car at ~1000mph directly west to exactly oppose the spin of the Earth.

Yes, due to gravity which overwhelms all other forces by several orders of magnitude. I thought you didn't believe in gravity though.

 

Just forget it. You obviously can't keep track of 2 things moving relative to each other in your head. If you would, you would see that an object thrown would impact the Earth again as their paths intersect.

Edit: It isn't gravity that overcomes anything. It's the momentum the object still has in the direction that is, at the time of impact, towards the center of the Earth. If something falls from 100 meters and takes 4.51 seconds where is the point where it lands 4.51 seconds from the time it started to fall?

 

NO NO NO NO NO!!!! The Earth does not movie STRAIGHT into the path of the "falling" object. The object will impact the Earth on its "side", for lack of a better way to describe it. It's because the Earth is a sphere and it rotates at about 45 degrees relative to the resultant vector of the momentum imparted on it by the Earth. Do a vector addition calculation and you should be able to see it.

 

This is just crank nonsense that goes on and on.

 

Only if their paths change. Otherwise their momentum keeps them moving in a straight line away from each other.

You can claim the the Earth is somehow constrained and not moving in a straight line. But what force is changing the motion of the thrown object? As I've mentioned before, since the effect works all over the Earth you cannot postulate that the Earth is "moving into the path" of all the thrown objects, all over the world. And objects move in a straight line, maintaining their speed, unless an external force acts on them.

Right. But you postulate a thrown object whose direction is AWAY from the center of the Earth. What changes it?

You're using that word, "fall." Fall implies gravity. Do you now accept gravity? If so you can use the basic formula D=1/2AT^2, where A is the acceleration caused by gravity.

Without A, though, you can't use that formula.

 

It doesn't change direction. It still moves straight.

Are you thinking of the Earth as just revolving around the sun and rotating? It revolves around the sun at only about 13% the speed revolves around the galaxy.

Maybe you can help me help you. If 1kg object has 212000 kg m/s of momentum at a 112 degree angle, how much force does it take to move it 6,378.10km over 6 hours at a 336.56 degree angle?