Recent content by bgq

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Hi, We know that a varying magnetic field creates and induced electric field, and a varying electric field creates an induced magnetic field. If there is a varying electric field (let's say sinusoidal), then this electric field creates an induced magnetic field. And if this produced magnetic...

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Hi, It is usually claimed that a person in an accelerating elevator with an acceleration equals to the gravity of the earth; this person cannot make any experiment that makes him know whether he is in the elevator or on the surface of earth. However, if this person project two light beams...

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Hi, If the microscopic world is not deterministic, then naturally the macroscopic world should also be not deterministic because it is based on the microscopic world. The problem is that the macroscopic world is deterministic; the evidence of this is that a lot of our technology and...

OK, thank you all very much :smile:

Actually, I have completed two years general physics in university, I have learned that the sources should be coherent (talking about interference). A student in the secondary school asked me about synchronous. In his textbook (translated from french), they say about the conditions of...

Well, is this mean that "coherent" and "synchronous" are the same? Is it just a linguistic issue?

Hi, What is the scientific definition of "synchronous sources" when we talk about the conditions of interference? Thank you.

Oh, I missed this point. Thanks a lot. I will try to do it again.

I don't remember the URL, but here is my work. Let M be the mass of the spring, L is its length at any time t, and V is the speed of its free end at the time t. Let x be the distance from the fixed end of the spring to any infinitesimal part of the spring, and v is the speed of this part. Let λ...

Hello, Just for curiosity... Is Hooke's law valid for a vibrating massive spring ? I have done some calculations using both Newton's 2nd Law and the conservation of energy to a horizontal swinging spring connected to a small block in the absence of any friction. I have found that the tension of...

Neither towards nor away. In this case the received frequency would be the same as that sent by the source. Is this true?

I don't have a problem that energy depends on the frame. What confuses me is the example in my previous reply where energy appears not to be conserved with respect to the same frame.