I agree that we have been reading differently. I'm sure there are statements in this thread that are open to multiple interpretations, but nowhere has metalwing unambiguously contradicted this basic claim. If you think otherwise, maybe you read something into his words that weren't there.




as i've said and continue to say, gravity is not the only force affecting any object.

only if the velocity can be maintained. the effects of drag will slow the bullet, assuming that it's fired within the atmosphere and gravity WILL effect the fired bullet just as it effects the dropped bullet with equal force. but it will take some time for the force of drag to lessen the velocity to a point that gravity will overcome velocity and the bullet will begin a decsent and eventually strike the ground. solar wind notwithstanding, such form drag does not affect the planets in orbit so they've remained in orbit for billions of years. even with such forces as solar wind acting on the planets they've remained in orbit all this time. why? the force of momentum due to their velocity. like the bullet fired at orbital velocity the moon does not rush to the earth at 32'/sec2. nor does a sky diver who will eventually reach terminal velocity for the body position he maintains. the acelleration of gravity, 32'/sec2, is acting upon the skiy diver, aa force. and obviously we agree not the only force acting upon him.

JR, you really don't understand the physics involved. Your statement from above ... "but it will take some time for the force of drag to lessen the velocity to a point that gravity will overcome velocity and the bullet will begin a decsent and eventually strike the ground." is absolutely false and you have repeated it over and over in this thread.

You have stated that the aerodynamics provide lift to the bullet. It does not.

And the moon is falling towards the Earth at the acceleration it's distance from Earth dictates, it's horizontal velocity just happens to exactly cancel the vertical component.

You have stated over and over that the fired bullet will take longer to hit the ground than the dropped bullet. It will not.

I agree on those points. Terminal velocity of a bullet is far, far lower that orbital velocity, so the conversation about orbiting bullets was just to illustrate a principal and has little to do with the reality of ballistics of handheld weapons on the earth's surface.



Actually muzzle velocity is also far lower than orbital velocity, so metal is right: the bullet is descending from an orbital curve the instant it leaves the barrel. As metal stated at the beginning only the slightest correction due to the curvature of the earth may be necessary; otherwise the dropped and fired bullet take equal times to fall. The idealized notion of orbiting bullets doesn't change this fact.




I only brought that up because you used the phrase 'only force acting', instead of 'only significant force acting' while representing the claims of others - I think we can (and should) leave solar wind out of this conversation as long as we are careful with our use of the word 'only'.




I think this is the heart of the misunderstanding here. To a physicist, the moon is rushing at the earth! There is subtly here and I think MW is right about you simply being unfamiliar with it. The moon is perpetually falling toward the earth in the inertial frame with the exact same acceleration as a non-orbiting object at the same distance from the earth. For some this is a surprising and counter-intuitive fact, and it might seem obviously 'wrong' since the moon never strikes the earth, but its true. The 'horizontal' velocity (I've been using 'horizontal' as shorthand for 'orthogonal to direction of gravitational force') the horizontal velocity does not change that downward acceleration! As MW has been explaining all along, the two act independently.

don't recall ever stating that aerodynamics provides lift to the bullet.

... and it cancels it only in the sense of 'overall change in distance from the earth', not in the sense of somehow magically diminishing that acceleration, nor providing a real force on the object.

but we were talking about orbital velocity. of course muzzel velocity doesn't come close. but a bullet fired at orbital velocity will begin to slow to a speed below orbital velocity due to drag and that slowing takes time. at some point it will be flying no faster than a bullet fired at muzzle velocity and further slowing will take more time all the while maintaining a decreasing horizontal trajectory. all this time the bullet is slowing at an ever decreasing rate as drag works on an object directly proportional to the square of the air speed. reduce the speed by half, you reduce the effect of drag four fold.

think of this senario. an appollo command module is in low earth orbit. it fires a decelerating thrust maneuver to slow below orbital velocity so that it will descend to earth. at some point soon after it will begin to enter earth's atmosphere still at a very high speed amountng to several mach numbers. suppose you were to drop an identical capsule from that exact height above earth where it began to enter the atmosphere and neither parachute packs worked. would they both impact the ocean at the same time? eventually the speedy craft will reach a vertical trajectory with no way to maintain it's velocity and then yes, it will fall at the same rate as the one dropped vertically but it will take some time before it begins to fall vertically and the dropped capsule will likely be bobbing in the waves by then or very close to it. trajectory is key here and this particular trajectory, not completely lateral but far less than vertical, is caused by the velocity no different than the lateral trajectory of the fired bullet at muzzle velocity vs the vertical trajectory of the dropped bullet.




i don't recall ever saying that there was an 'only force acting' on any object we've discussed here. can't count the number of times i've said that velocity is an acting force. and i didn't bring up solar wind.




hahaha. MW actually said an object in orbit is NOT falling toward the mass that it orbits. said that it's impossible for something to fall in space as there's no up or down. yeow. i think i first brought up the concept of falling as applied to orbital mechanics and he poo pooed it as my knowing not even high school physics.

i completely understand that the moon, a bullet, a feather or a coke machine is affected by the accelleration of the earths gravity and that that accelerative force is constant. they all fall toward earth because of earth's gravitational pull and that pull is equal to all. no, velocity does not change that downward force even though there is no down in space. lol. as you say, the two forces are independent but both are significant. after all, the distance from moon to earth is what, an average of more than a couple hundred thousand miles from earth? even traveling such a great distance, if it's velocity did not have an opposing effect to the force of gravity, how long would it take to impact earth accelerating at 32"/sec2? certainly a much shorter time than the 4-5 billion years it's been 'falling' towards earth.

many things counter the effect of gravity. i can place a full cup of coffee on the instrument panal glare shield of an airplane and perform a barrel roll passing through inverted flight and if i do it well i won't spill a drop of coffee. you can step on the scales in alaska and weigh less than you will at the equator, both due to centrifugal force acting against gravity.

So we all agree this doesn't happen in reality, with handheld weapons on the earth, right?

You agree that both dropped and perfectly-horizontally fired bullets fall towards the earth with the same acceleration? And if there ever were any minuscule difference in the time to fall to the ground (fired over a perfectly flat surface), it would be due only to the curvature of the earth?



Are you seeking to establish a point? If so, specifically what point are you trying to establish?




Usually that expression "I don't recall saying..." is used when someone else has claimed or implied that you did say such. Is that why you use this expression?



I think you made a typo, there. Care to fix it and we'll go from there?



Um, no, you are wrong. MW said no such thing. IMO, you really ought to pay more attention to what people say if you are going to have a conversation with them.

And here you are expressing amusement based on your own misunderstandings.




This is exactly the edge of your understanding of physics. This is exactly the place at which you should start asking questions rather than making statements. There really are high school physics books that address these issues.

BTW, this has been irritating the hell out of me but I was trying not to be pedantic or anal-retentive, though one must precise and careful to use physics properly. Your value for the acceleration due to gravity, in this context, is wrong. Do you know why?

yes, yes and no.



establishing nothing whatsoever.




no. i USUALLY use the expression when i want to express that i don't recall saying something.





outside of being too lazy to lift my pinky over to the shift key is see no typo.



you're right. looking back i see it was jeannie who poo pooed the falling. and i'm on a dating site ONLY for my amusement.




that folks get irritated on a dating site forum is what i find the most amusing actually. but i'm amused when i learn something new as well. so if my value is wrong in this context feel free to enlighten me. calm the irritation first if you wish. or don't.

If I wasn't losing patience, I would take another stab at exploring the basis for your 'no' answer.

In any case, metalwing is simply correct. If you think otherwise, I'll be more than happy to respond to a direct quote of his and a clearly stated reason for disagreeing with that quote.

i've been discussing a topic. made no claims whatsoever. in discussing this topic i've not once posted a link to a website quote, youtube video or anything else like so many do to make an argument that they can't make themselves. i've disscussed the topic using only my understanding of the topic. plenty of folks have contributed what i see to be from highly uninformed minds on physics. i can go to the religious forum and debate creation vs big bang all day but i would never, ever question their learning of hs physics as you and mw have done with me. why? because a person's schooling or lack thereof has nothing to do with the topic being discussed; in this case, a new theory about the solar system. the topic on these forums is never about who knows what better than who. sure, some here think it's all about how much more educated they are than others but it isn't about that at all. it's an open forum.

you talked about what people USUALLY are attempting in an earlier post. it was usual to you, not to me. but here's a USUAL something i often see on forums. i see people become IRRITATED because they are unable to convince others that their point is correct so instead of establishing their point further they make some inane comment about their opponent's knowledge or understanding. as if anybody here is in a position to accurately judge anybody's educational prowess based solely on what they read here. my view only of course but i think these 'knowledge judges' become such thinking that by commenting on a person's lack of understanding of hs physics, for instance, this attempt to lower the opponent's learning somehow raises his own learning and understanding on high. it never does, of course, nor does it ever add anything whatsoever to the point he's trying to make much less the topic at hand. and in this case what you and mw think of my attention span during hs physics has nothing at all to do with a new theory about the solar system. but like i said. amused when a thread becomes all about jrbogie.

No, what you have been doing is pretending that you understood physics and making false statements. This is the SCIENCE forum. When someone like you states the moon is made of green cheese, and means it, there are going to be those who laugh and those who point out the error of your ways. You have made numerous false statements about physics in this thread and have relentlessly stuck to your guns that you were right. Now you think that someone pointing out the factual errors in your statements are personal attacks ... which also isn't true.

Four people here have pointed out the "problems" with your statements concerning high school level physics. You have just continued making more or repeating the same ones. Now you think we are trying to "put you down" to make ourselves feel bigger?

Everyone is welcome to their opinions in the Mingle community but false statements about proven science will attract just the kind of comments you are getting. Science REALLY isn't your subject but you seem to want to pretend that it is.

You would look much smarter if you would use questions instead of false statements.

And for the record, the old science of how bodies move from gravity is largely what this "new theory" is all about. If you understood why a dropped bullet hits the ground at the same time as the fired bullet (even one inch from the ground) you would understand why.

A claim is simply a statement about a topic, an assertion that something is true. It seems to me that you've made many claims.



Do you see this as a 'good thing' ? When it comes to science, I think its much better present reliable references than to not. I was being lazy by going off of memory for the equations above. MW was taking a more respectable route by posting links to accurate sites.

Science isn't about proving who can argue better - its about getting to the truth of the matter.



Yes, you are absolutely correct! Ignorance itself isn't a judgement, we are all ignorant in some ways, and in our ignorance we can still contribute to a dialog.

Some of those people with 'uninformed minds' you mention even get really argumentative and make wrong assertions. If they come across as crazy or too stupid to argue with they might just get ignored - otherwise they are often corrected. You've seen me get focused, tenacious, and argumentative with others because I believe them to making false assertions.



Its not so cut and dry as that. Everybody should be able to participate in a discussion, but I feel that the form of their participation should be influenced by the degree of their understanding. I will flat out tell people they are wrong in many conversations involving science, but I'll have nothing but questions if the topic is, say, painting.

I agree with you that formal schooling itself is irrelevant - but the degree of a persons understanding is absolutely relevant. Our respective understandings, along with the approach we take, has a definite influence on the movement of the conversation as a whole, and the value that we each get from the conversation.



No, but it is about 'what is true'. What MW has said was true. I was quite baffled when I skimmed through some of these pages and saw people being so argumentative with him.



Anyone who thinks that their education, alone, ensures their claims are accurate is a fool. I've known many educated people who lack thinking skills, and uneducated people with exceptional thinking skills. My memory is poor, so a lot of the potential value of 'being educated' is lost on people like me; there are many uneducated people who have learned and remember far more than some educated people. This isn't about being educated, at all... it is about getting at the truth, and speaking from places of understanding.




Fair enough.



I was irritated because there was so much sloppiness, imprecision, and errors of fact in this conversation. I think its good for scientists, students of science, and seekers of truth in general to be have some emotional impetus to higher standards than this. This kind of irritation can be beneficial.



I have no idea, and made no comments about, your actual experience in high school. Since I've personally forgotten a huge percentage of what I've learned over my life, I would not assume that a persons current lack of understanding implies that they never understood.

I'm not happy (and right there, thats my own problem, not yours) with the level of attention to detail you have brought to this conversation. Any statements I made about your attention were related to that, not to your high school experience.

Also, references were made to 'a high school level'. This also makes no implication about your high school experience. Much of my writing is below a high school level in terms of grammar and sentence structure. That doesn't mean I did poorly in english in high school.

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Seriously though.... all ya'll shouldn't be so quick to argue with MW about any application of newtons laws. I don't recall a single time he's been wrong on that topic, so if you disagree with him its probably time for questions rather than assertions that he's wrong.

It is true...

The Earth does not orbit our sun.

The Earth orbits a point where its gravational forces are in balance with all the forces present within the Suns space time vortex.

True, it's called the center of mass. I think the point where the moon orbits the Earth (and vice versa) is about four thousand miles from the center of the Earth.

Has anyone calculated the center of mass for our solar system?