# Search results

1. ### Exact meaning of F=dp/dt

The second law states that the force on a body is proportional to the rate of change of linear momentum. We work in units where the proportionality constant is 1. You could in principle, define force to be that quantity which is say, twice the rate of change of linear momentum. You would...
2. ### Why do we make arithmetic mistakes?

Thank you all. It is much clear now.
3. ### Why do we make arithmetic mistakes?

I wrote conscious; not on purpose. Maybe voluntary is the appropriate term here. What I mean to say here is why does our brain make arithmetic errors when it comes to making "conscious" or "voluntary" operations such as mentally adding two numbers. For example when someone asks us what 9*9 is...
4. ### Why do we make arithmetic mistakes?

I know the question does not strike as being specific to physics, but please, give it a look. Human brains are considered complex computing machines and are rightly so as seen by the examples around us. Why then is it that we make conscious arithmetic errors( For example: calculating...
5. ### Limit of charing a body by positive charge

There are other ways to charge a body. You can always add a positively charged particle to it.
6. ### Potential of Brownian particle

No, we don't. And as far as I remember, this is not a forum where ideas of humor are discussed. You might very well have been a person who makes the common mistake. I don't need to "get a grip". Peace out. Can you cite a source? I searched extensively and nowhere did I find this convention.
7. ### Potential of Brownian particle

In-case you're trying to refer to people who study physics, they're called 'physicists'. A 'Physician' is a professional who practices medicine. Please be more elaborate. I have not studied brownian motion in depth but I can surely say that \dot{x}(t)=\alpha(t)+\beta(t)\eta(t) can...
8. ### DNA origami

............... Not the sort of help i expected. Incase this post was ignored because other fresh posts coming, this is just to bring it up again. Please, I need help.

okay. :)

I mean, I use windows and so do many of my college friends using physics forums. I know it's an upcoming platform but still seeing the stability of the system, it's gonna stay for long and the app won't be built for nothing.

Need developers?
12. ### DNA origami

I'm working on a project in the field of DNA origami and need links to research papers and study content for the trapping processes and folding processes. Can anyone help?

Is the windows phone app in development?
14. ### How to proof the polarity of the reflected wave of Oblique incident.

Try solving the problem there. I faced the very same hurdle. The boundary conditions beautifully bring out the result
15. ### Expected value operator.

Thank you! This and the accompanying statements cleared a lot. I was confusing between the two. And yes, according to the law, E[g(x)] = Ʃf(x)g(x) does give the same.. In the example provided by you, where f(x) = 1/3 : x ε {-1, 0, 1} and g(x) = x2, E[g(x)] does indeed give 2/3. It is clear now.
16. ### Expected value operator.

this makes the value equal to 2/3. But according to the definition, and this makes the expected value of g(x) equal to 4/3. What is going on here? Forgive me if I'm being too sticky about this, I just need to clear the dilemma and I certainly appreciate your help.
17. ### Potential Gravitational Energy into Force

For static cases, yes.
18. ### Expected value operator.

I got a vague idea about what you're talking about. Tell me if I'm wrong: According to what you say if Y=g(x) is another random variable and h(y) is its distribution, then E[Y] = Ʃ h(y)*y for the discrete case. ie E[g(x)] = Ʃ h(g(x))*g(x). And this is said to be equal to E[g(x)] = Ʃ f(x) *...
19. ### Magnetic field relativistic effect

There is a current there too. Its just at a very small scale. All individual matter particles found around us have an intrinsic magnetic moment associated with them. But they are, in general randomly oriented and in non-magnetic substances, more or less cancelled out. In magnets ( for example...
20. ### Expected value operator.

While reading the article:Law of the unconscious statistician, I came across a line and then a few lines after that, the expected value of a a function g(x) is said to be given by: ∫f(x)g(x)dx. However, if g(x) is not explicitly known, how does one calculate the integtral?
21. ### Perpetual Current Machine

russ_watters is right. The magnet will be repelled to and fro between the two larger magnets, sure.. But the oscillations will slowly die and and the magnet will eventually come to rest in a position where the two repelling forces are equal. Ofcourse, there is the inductance of the coil...
22. ### Radiation from a charged harmonic oscillator

Hello HomogenousCow, maybe this will help:
23. ### Coloring pixels

Okay, so not linear then. More like Polar? Involving sine and cosine relationships? Yeah, Borek pointed that out. I guess looking from the point of view of the wave theory, a function describing the relationship between Intensity and frequency can describe a pixel's color. I guess the...
24. ### Physics problems related to green function ?

Try simulating a classical damped, driven harmomic oscillator. I'm assuming you're working with Fourier transforms, yes?
25. ### Tricky 2d motion question

Let the velocity be v. then the horizontal distance is D = v*(t=2.792). Then, apply the pythagorean theorem sqrt(D^2 + h^2) = 343*0.338. height of the cliff (known).
26. ### Coloring pixels

So wave theory and color theory are two completely different models. Its like looking at say, a computer from two perspectives: As an electronic device and a turing machine.
27. ### Coloring pixels

And adding just one more parameter covers that up?
28. ### Coloring pixels

I was working on an image processing project a while ago and was specifically working with raster images in the Hue-Saturation-Value(HSV) image format. Each is determined by mathematical values of these (HSV) parameters. I also worked with other bases such as the Red Blue Green (RGB) format. Now...
29. ### Java Learning Java from the makers

For learning C and for references, " The C Programming Language" by Dennis Ritchie and Brian Kernighan is an authentic. Which book should I refer to if I need to learn Java the same way?
30. ### Photon as a wave packet

So what you're saying is that even a neglible frequency range is enough to limit the spread of the group from infinity to a few nm, right?