EPTPhysics: I am feeling quite silly - Page 2
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Crankenstein
Australia150 Posts
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lofung
Hong Kong298 Posts
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exeexe
Denmark937 Posts
A force (F1) is being exerted on an object and you want to counter that force with your own force (F2). Naturally those 2 forces would have to be equal because you want your object to be stationary hence: F = force F1 = F2 But you want your answer to be in power .. kk In order to answer this we must see how far the object travelled because ![[image loading]](http://upload.wikimedia.org/math/7/6/8/7680d79cfc1c61f21fe00e1089a9493b.png) where C is the path the object travelled. So we see that d is 0 because it was stationary, that is, the power for the complete system is 0 - but that wasnt what you asked about. You wanted to know how much power you had to exert to keep it in balance. Well in order to answer this we must set F1 = 0 so there is no force. Now that the forces are no longer in equilibrium the object begins to move, and it begins to accelerate. Now we see that d is no longer 0. Actually d is ∞. That is because you have not specified for how long time you want to exert your power. Should you exert power for a period of time then you can find d and d will be a valid number somewhere between 0 and ∞.. Then you can calculate how much power YOU and not the system exerted. | ||
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SlimeBagly
356 Posts
The path length is zero- so your integral has the same lower bound as upper bound, so it subtracts to zero. | ||
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exeexe
Denmark937 Posts
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matjlav
Germany2435 Posts
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Zilver
Finland282 Posts
On December 25 2010 23:35 matjlav wrote: Yup, the answer's zero. Think of some object sitting on a table: gravity is being constantly exerted on the object, but the table is keeping it still with no power expended. The energy that bonds and keeps the atoms solidly together is what's keeping the object stationary. | ||
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matjlav
Germany2435 Posts
On December 26 2010 00:36 Zilver wrote: The energy that bonds and keeps the atoms solidly together is what's keeping the object stationary. The energy isn't expended to holding up the object. It just exists, so no power is required. That potential energy isn't holding up the object; the forces of intermolecular attractions and repulsions is what's holding the object up, and force is a distinctly separate concept from energy. | ||
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Nuttyguy
United Kingdom1526 Posts
your confusing power work and energy | ||
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