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### Physics FAQ

Quality answers to common physics questions
May25-09 11:31 AM ZapperZ

# General Physics

- Nature and properties of matter and energy. For any physics topics not applicable to the categories below.
 Views: 762 Announcement: End of year contest, $75+$50 prize! Dec18-13 Meta Thread / Thread Starter Last Post Replies Views Pinned: Recent Noteworthy Physics Papers ( 1 2 3 ... Last) The aim of this thread is to highlight recent (as in within the past 3 months) noteworthy physics papers that have... Dec9-13 04:47 AM Cthugha 162 151,726 Before posting anything, please review the Physics Forums Global Guidelines. If you are seeking help with a... Apr22-11 06:27 AM ZapperZ 2 60,615 Ok, here we go. In a rotating mechanism (helicopter rotor), at a state of equilibrium, the rotor consumes a certain... May16-12 08:35 PM russ_watters 4 944 This is my situation: I am on a roughly 250m hill and trying to see sea-level sunset, but there is another hill 4-5km... May16-12 06:32 PM tiny-tim 4 951 In lectures we have been given: ## \vec{\nabla} \cdot \vec{D} = \rho_{\text{free}} ## ## \vec{\nabla} \times... May16-12 06:10 PM cabraham 7 863 If helium 4, when it is a super fluid has no viscosity then you shouldn't be able to float anything in it. And if you... May16-12 06:00 PM oliverhennigh 10 1,468 What is the cost for 1 hr? Current = 1 A Voltage = 25 000 V Kilowatt hour = £0.10 KWhr May16-12 04:56 PM berkeman 1 916 How is the magnetic moment of a bar magnet treated in the equation τ=μ x B? How do you determine the angle theta in... May16-12 01:11 PM runphysicsrun 0 831 Is there any way to cataclyze the recombination of oppositely charged ions? I'm wondering if an effective method... May16-12 11:50 AM Bob S 4 901 Hello, Is there any research available as to whether Newtons Law F = mg should include horizontal surface area as a... May16-12 10:21 AM Whovian 13 1,253 Suppose I have a rigid circular metal plate that takes sound X microseconds to cross. What frequency would I have to... May16-12 09:55 AM nasu 2 694 In my experiment based on the inertia the angular velocity or speed goes either up or down with the angular momentum... May16-12 07:32 AM tiny-tim 2 1,361 Hello. I stumbled upon a video on youtube where quantum entanglement is discussed... May16-12 04:47 AM ImaLooser 1 1,644 Hallo everyone! I was wondering is it possibile to use magnetic attraction/repulsion to increase speed or... May16-12 02:09 AM Hypo 20 1,921 Throughout the journey of an aeroplane flight, the magnetic field of the earth will induce and electro motive force in... May15-12 10:12 PM Wharton8 1 732 I have deposition rate of Silicon dioxide as 1000A/minute. I need to calculate molecular flux to the surface. First I... May15-12 06:09 PM Ravian 2 879 not knowing much of anything about light physics, is it possible to change the effects of a prism (the visible... May15-12 05:30 PM K^2 2 740 Hey Everyone, I am working on a project that uses induction to charge a widget by placing it within an EMF… just like... May15-12 02:48 PM sourapple 2 720 Hi guys.. I want to find out how to find the maximum speed of a slotcar at a unbanked turn with a permanent magnet... May15-12 10:17 AM anru 2 995 Hi, I was just wondering, is mechanical energy conserved when two cars of equal mass and moving at equal speed... May15-12 09:55 AM Whovian 2 785 It sounds like an easy-enough problem, but even writing down the ridiculously nonlinear equation that would need to be... May15-12 08:17 AM jjustinn 3 1,107 Guys i really need your zealous help! It is a simple concept but i have some doubt on it. A vector can be resolve into... May15-12 06:37 AM azizlwl 5 1,572 Hello, I was googling for the characteristics of an acceptor circuit but didnt find what i was actually searching for... May15-12 12:55 AM NascentOxygen 1 1,667 In order to make something into degenerate matter, can you just put massive amounts of energy into compressing it once... May14-12 11:47 PM scijeebus 0 606 If light is going away from you but get's curved positively, does it red-shifted or blue-shifted? Er, I guess you'd... May14-12 11:33 PM scijeebus 0 603 I am reading in my textbook an example problem. In this problem, there is a rope tied to a boulder on one end, and on... May14-12 11:09 PM Steely Dan 4 805 Hello, I do not manage to visualize the link between the component of the quadrupole Q_ij and the spatial... May14-12 10:17 PM Bob S 5 946 Lets say that this is hypothetically possible;How much energy would be required to sink an Island the size of... May14-12 08:02 PM davenn 4 1,242 To show that entropy is not the same thing as disorder (what people intuitively accept as disorder) my textbook gives... May14-12 07:29 PM roam 15 1,988 I have read about how magnetism arises from electric interactions and relativity. But in that respect i dont see how... May14-12 06:21 PM guillefix 7 1,529 The energy stored on a charged capacitor is 0.5*Q*V or 0.5*C*V2 BUT what is the electrical work done by the supply... May14-12 04:24 PM truesearch 55 4,482 Hello, I am working on a paper about maglev systems and am trying to describe attractive electromagnetic suspension... May14-12 02:58 PM maimonides 4 1,158 What is Bermuda Triangle? Is gravitational Forces exist there or not? May14-12 01:10 PM DaveC426913 7 1,434 If work is displacement times force, lifting a weight up and bringing it down to the same spot would have zero... May14-12 10:06 AM sophiecentaur 2 1,429 I have been thinking about the logic of resolution of a main force into its component forces. Up to my stage i have... May14-12 05:01 AM sophiecentaur 4 1,580 Hey guys, I had an interesting thought so joined now so i can see what you all think. I was thinking about what... May13-12 11:34 PM AmPure 0 800 Does electric field vary with distance? For example, When I fix an electron along an axis and then fix another... May13-12 10:18 PM cragar 1 820 Both pressure and stress are defined in terms of force per unit area. Beyond that simple relationship, what might... May13-12 08:30 PM Andy Resnick 3 4,204 Hi, I just want to understand this concept a bit better. The law states that momentum is conserved when there is... May13-12 03:29 PM Michael C 7 1,283 What determine the place at which a given material gets magnetically saturated? I have measured the hysteresis of a... May13-12 01:07 PM andreasbaldur 0 866 Which way did Newton find F = ma? ( 1 2 3 ... Last) I was under the impression that, by experiment, Newton deduced \textit{F}\propto{m} \rightarrow \textit{F =... May13-12 03:00 AM prosteve037 73 11,909 Suppose I have a plasma. Inside the plasma is a knotted flux tube in an electric field. Will it tend to move? Is... May13-12 12:32 AM ImaLooser 0 612