Psychological Experiment: Guess the answer to physical question.
I'm gonna guess never. Some other crap in space will probably effect them first. If that doesn't happen then 4.65427 billion years.
1 cm copper ball is what, a few tens of grams top? Earth is about 10^26 more massive, gravity would be 10^-26 less... would take 1/10th second to drop on the floor, gravity law is square root, 10^13 * 0.1 sec, 10^12 seconds, ...30,000 years or about? Cant believe I tried to work it out.
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Quote:Original post by ApochPiQ
Mmmh... I don't agree. IMHO the more factors that have to be guessed, the less likely you are to get any meaningful data on your actual question. In other words, making us guess the mass is going to introduce yet another inaccuracy in the calculation, which will skew the results towards inaccuracy (unless someone gets lucky of course). This means you introduce sampling noise into the experiment; you're no longer testing the ability of people to think in both large and small numeric terms - you're testing the random luck of people to guess an overly complex problem.
actually, there's a point in not giving density of copper. I'll explain it later; for now it suffices to note that the guesses at the time here range by many orders of magnitude, whereas guesses at copper density most certainly do not range even by 1 order of magnitude (and the impact on final value is even less). edit: and this is not a contest; this is a psychological experiment involving collection of responses.
Would two feathers move together with the same acceleration (profile) as two canonballs ? - I liked chemistry more than pyhsics so i dont know. My guess, faster than my current refactor - about 2 weeks.
So the spheres are identical, made of copper, and are located in empty space flying away from the stars (and all the associated matter). Are the spheres traveling at identical velocities? Are they gaining speed? If they started at rest, and they're flying now, then they must have gained speed at some point. Are the spheres rotating as they travel? Were they launched from a rifled tube? No matter. Let's assume they have the same momentum and the same inertia. Isolated from external interference, they will never touch. As long as they are moving in parallel, they will remain in parallel. The initial force that propelled each sphere is so much greater than the force of gravitational attraction between them, thus the gravitational attraction between them remains negligible as far as their trajectories are concerned. Unless the two spheres encounter a resistance capable of draining them of inertia, they won't ever touch.
The question in the OP suggests that they will eventually, but I think that's where the psychological angle comes into operation. The suggestion that they will touch frames the question in a way that leads the audience to want to satisfy that suggestion rather than apply what traces of physics they might remember from school. Satisfying the suggestion takes psychological precedence. Subsequent remarks about the involvement of big and small numbers, in as much as they introduce notions of scale, reinforce the suggestion that the spheres will touch at some far off point in time.
Heavy Boots! [grin]
The question in the OP suggests that they will eventually, but I think that's where the psychological angle comes into operation. The suggestion that they will touch frames the question in a way that leads the audience to want to satisfy that suggestion rather than apply what traces of physics they might remember from school. Satisfying the suggestion takes psychological precedence. Subsequent remarks about the involvement of big and small numbers, in as much as they introduce notions of scale, reinforce the suggestion that the spheres will touch at some far off point in time.
Heavy Boots! [grin]
Quote:Original post by LessBread
The initial force that propelled each sphere is so much greater than the force of gravitational attraction between them
That shouldn't matter, remember relativity. Without an external point of reference, you wouldn't even know that they're moving.
It will take exactly One Copper Ball Centimetre (CuCm), a unit of time which is defined as being exactly equal to the amount of time it takes for two copper balls to attract each other a total distance of one centimetre, where the only acting force is their own gravity. [grin]
Quote:Original post by YsaneyaQuote:Original post by LessBread
The initial force that propelled each sphere is so much greater than the force of gravitational attraction between them
That shouldn't matter, remember relativity. Without an external point of reference, you wouldn't even know that they're moving.
They are flying away from the stars. There's your external point of reference.
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