Bryce

OK, So i figure now that the ball on a string is just like a ball on a shelf.

Not true, I did read through. but Obviously something has not hit me yet. I appreciate the effort, and i can see you did go to a great deal of effort for such as me, I value that, and, I will go back over it later, I added my post 65 just to clarify my previous post to that, I have not had time to concentrate on what you have posted. I have my kids for the weekend, and my little 4yo girl is the master of knowing when to get up and ask me questions, her timing is amazing. but without that as a distraction, I may never get it. I may have to just accept it, but, here's to hoping I do. Have a good weekend and don't worry about me . PS this sort of diagram is not unfamiliar to me, and it is very similar to what you presented. though, in that diagram, there is a component that is affecting the velocity magnatude same as your fig7 F2 As lift is opposing gravity, and they are both opposing each other with equal magnitude they are zeroed out, Most reputable RCGroup members will say that there is no work done to maintain levle flight other than drag. (AFAIK, they are right) So i guess that if the plane flys around the world once, it would be similar to the ball on a string or a satelite in orbit. Why am i trying to break it down and examin the change in inital velocity as 1m/snth over the 90deg of rotation i dont know, I think i will stop that now OK, have to go for real this time. little one has asked me 7 times if we are going to the park, hard to concentrate.

When I said Isolate, I was talking about reference frame, an isolated system, not an isolated example with special conditions. I was going to mention an example of an isolated reference frame of the earth sun and galaxy. they are all moving around each other in the ways they do, and it may appear from day to day that there is a displacement. but , when you look at them in their individual reference frame, IE earth around the sun, (every year we end up with no more Distance from the sun no more speed and basically in the same place. same with the sun around the galaxy, But I refrained from it because all the orbits are not perfect and the forces are changing such as the suns gravitational pull (and I don't actually know if it's getting less or more , it would seem logical that it is getting less) anyway, it was not a precise example, but it was an attempts to show an isolated system.

Is this all unique some sort of Isolated system observation? our goldfish as we observe from outside is changing speed and direction relative to us. but it is almost irrelevant because, well, we are not influencing it in any way, so, we are not part of the equation? If it's not because of an isolated system observation then why ignore the fact that speed in both the north and east direction was changed ? PS Thanks and Have a good weekend, get back to this later

Hi Studiot. if the velocity is seen as its path velocity, then the speed did not change. I understand that work is the change in Kinetic Energy, and that Ke is defined only by the speed variant of Velocity, not the direction. but doesn't changing direction require work to be done, or in our case, where you spin the ball on a string, the velocity is changing as direction only, but if you change the reference frame to that of an outside observer who is seeing you swing that ball around in your glass windowed truck, the speed is changing relative to them. OK i get it. the kinetic energy is not changing relative to the pole it is fixed to, but relative to any other independent observer the KE is changing. I recall some time ago that someone pointed out that after one revolution there is no change in position so no work was done. and it makes sense that a if work was done how come neither of the variables have change in the formula ke=1/2MV^2 it has the same mass the same speed and direction. so there could not have been any work done. (I am at home now and i was when i last posted, so i guess i have not done any work in the meantime ) So here was my assumption, I chose this assumption to help me sleep at night, there was work done, and it can be seen especially after each half rotation. but each conceutive half rotation will be work done in the opposit way so it will come back to zero. And now I have thought about it some more, I am back to your camp, with the ball on a string or even any two points of a rotating body, if there was work done and the energy was always present but nulling it self after each half rotation, where did it come from? (My previous example was given to me years ago as a satellite in orbit, i mistook gravity as energy or a force, but now i see it as something else not too much unlike the bonding of all molecules in our spinning body. for a lack of a better work i would call it a force) five min later I come back to make another post, it gets added to the last one I noticed.. Second post is as follows; Oh mann I think I am having another cerebral flatulence moment. I think I can say yes there was work done, and point to where the energy came from. in the case of the satellite and the earth, the energy was traded between each other as speed and height change relative to their CoM. a form of ke pe change. same with the stick. the stick bent and stored potential energy or if it's in your hand you were providing energy or if you were in a car the cars speed changed..... but, if it were two balls of equal mass rotating around each other then they would have no speed change relative to CoM and no height change hmmm. oops fell into a hole just then. BrB Back again, changed CoG to CoM. OK now i am just now realizing they (The earth and satelite) don't change distance/height position relative to their CoM, they rotate uniformly around it. hmmmmmm.. Back in a day or more.

thanks for the guidance Seth. Thanks for the reminder Swansont Think i will go learn calculus. back in a while

I have a feeling you may laugh at me, and i beleive it is justified, but..... true to my previous posts form, i will suggest and accept the ensuing lecture/schooling. OK balls out again, I hope they stay attached with this one. Is the reason the mass-energy formula is twice as strong as the kinetic formula due to a unique thing about that formula. it is the energy that was contained within that mass should it be broken/released into sub-atomic particles and various other forms of radiations, Thermonuclear stuff (Stuff I know nothing about). the formula does not need to be devisable to obtain some sort of constant velocity because as you know , the speed of light is constant. but here is a question, aren't the subatomic particles released at the speed of light ? I am thinking there is no acceleration upon release, there was only acceleration of the particles as they were, in the atomic structure prior to release, IE they did not start from a stop position, they were and are energy (Energetic subatomic particles whos mass is derived from velocity contained within a volume by the strong force. I am currently imagining it like two balls on a string (String representing the strong force), They rotate around a central location held in proximity to each other through their bond (The string) the two have no other motion other that that rotational velocity, so as a pair they have no translational motion. the two balls are accelerating around each other until the string is broken, and at that point, the acceleration stops and the velocity becomes consistent as speed in a uniform direction. OK, laugh time over oh wow, even I can see how vague all that is, no doubt most will just scoff at the lack of knowledge I have regarding atomic and subatomic particles and their working relationship within their bond, (I have so many questions, I think I need to watch a few good animation on this).

Awww man, I nearly understood that until you mentioned Proportionality, it was entertaining for the lay like me. I decided to look up that word (Proportionality), It turns out I understand it as coefficient, I see that the use of the word proportional can be tricky, Bugger.... it took me a while to learn to use the word Velocity speed correctly and acceleration set me back completely, Satellites accelerating around the earth all the time O.O I guess now, I do have the ability to learn, But it seems I only learn at a rate proportional to the effort i put in, i only wish i had some sort of exponent to help that along. OK> i need to develop a mathematical vocabulary, my words for this month (yes a month lol) are proportional, Coefficient exponent PS Lift = Cl 1/2r V^2 S I think I understand why the lift formulas Proportionate "Cl" works, basically it has to do with the shape and the way it causes an acceleration of air particles (mostly in the change of direction) though this is vague and nowhere near complete, I can say that the Cl value is proportional to the amount of curvature on mostly the upper surface, this Cl Proportionate will also change when you change the AoA, because, you have effectively changed the curvature relative to the air flow. So there is an acceleration hidden here in this value, and the lift is the result of some sort of Kinetic interaction. so the whole formula has the 1/2 value incorporated in it, and from what Seth was saying, the half value is a constant of proportion. so would that make Cl the second constant of proportion or ?? So I have typed all this out in an effort to understand, I want to know, now it's time to post it, but, I am a bit scared, should I just delete it or post it. if I don't post it I may not learn, but it's not your duty to help or to teach me at a dulled down level at which I stand, but there may be some willing to help and point out errors, so why not post it. OK, Balls out, here I go. Do you all use proportionate and proportional interchangeably or ?? Did I make many mistakes there with the use of the word "Proportional". any other errors/misconceptions I'm off now looking for the Fairy land Physics thought experiment room. Always liked them

Thank's Sriman, looks like I am stuck with my Mathematical blindness. the answers are there but I just don't have the time or intellectual fortitude to understand it

Hi Sriman, I am just a bus driver. I like Physics a bit, get headaches trying to translate formulas so give up most times. I probably should not be here, but the question intrigued me while considering the Oberth effect again recently, KSP lol. I also like RC aircraft and got into the physics of lift, Good old L= Cl 1/2 roh V^2 S , so the question of why we use half had been bugging me for some time (About 10years or more) but I never really found a suitable answer and gave up looking and just accepted it, I recall from my schooling back in the late 80's that it was from what I described. so given this information about me and how relatively dumb I am, can I truthfully ask. Is your comment suggesting my post is useless and not related to Kinetic energy and that it has nothing to do with the Formula KE=1/2*a*v^2 and ultimately not the reason it contains the "1/2" in the equation.

is this true, the 1/2 is because the change in velocity measured in m/s will not be the actual distance covered , such as 20m/s was the resultant change in velocity over say 4 seconds. so to times 20 by 4 would yield a result of 80 meters but it would actually only be 40 meters traveled during the time the force was applied to stop it. it is only 40 meters because the average speed while changing from 20m/s to 0m/s is 10m/s and 10 x 4 seconds is 40. This video may help explain what i am looking for. To the OP is this simple enough ? its how my brain works. no math, just simple explaining of why.