Mechanics - How to predict the motion after two objects collide in 2D?
I think no matter what are the mass of two objects, there must be a fix angle between the angle of two direction. Is that using the center mass reference to calculate? I say that because we can prove...
View ArticleProportionality of Traction and Wheel Slip
Hi All! I've been doing some research in an attempt to uncover the proportionality between usable traction, which is defined as the the product of coefficient of static friction and the normal force,...
View ArticleWhen you drop a ball from above, why doesn't it drill through earth?
First of all, I want to say that I am totally ignorant about physics. And I do not understand the general concepts of physics at all. Now coming to the question. Suppose, you drop a green tennis ball...
View ArticleWhy don't we feel the gravity of other objects?
Since every mass attracts every other mass according to Newton's universal law of gravity, why don't I just get pulled towards my computer monitor? Now you might say, the gravitational constant is so...
View Articlewhat IS an em wave?
i think i've asked this a number of times on different posts stemming from various discussions but i don't think this question was in the wrong thread. so i've decided to make a new thread for this. so...
View Articlewhat causes musical instruments to have different sounds?
harmonics... got it.. but for instruments, whether they have a sound cavity (brass instrument or woodwind) or a string, to be resonating at say, 400 Hz, they should both have the same resonant...
View ArticleGravitational Vortex Power plant
Does any body here have any information about gravitational vortex power plant..?
View ArticleIs max sound intensity at the displacement node in a standing wave?
Good afternoon all My question is, when we observe stationary waves, and we know that at a certain point, the sound is maximum, is this the displacement node or the displacement antinode? I have read a...
View ArticleFlow control valve principle
How exactly would you describe the principle of a valve for flow control? In a globe valve for example the fluid flows through valve seat and generally leaves the valve with the outlet diameter being...
View ArticleSnell's law for a conductor
Hello everybody! I read that if one of the two materials involved in Snell's law is a conductor, the refraction angle [itex]\theta_r[/itex] is about [itex]\pi / 2[/itex] and is independent of the...
View Articlefree fall trajectory in non constant gravitational field
Rusty on the math... I am working on a problem and need the derivation of a free fall trajectory for an object at a distance above earth where the change in acceleration is not negligible. How do I...
View ArticlePotential of a dipole with actual physical extension?
I think everybody here knows the equation that gives the potential of a point like dipole, but how does the field look like if you have e.g. a metal sphere with radius $R$ and a certain dipol moment,...
View ArticleCold wind and Hot wind
What's the difference between cold moving air and hot moving air? For instance, suppose you put two fans, of the same type, each in one room. One room is cold because the walls are covered in ice and...
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Please explain this from a text book
See attached scanned pages of page 118(left side) and page 125(right side) of Antenna Theory by Balanis. On the left side, it is just some basic EM where [tex]\nabla\times \vec E=-\frac{\partial \vec...
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Help calculating torque required
Hi All, I'm having a bit of trouble remember basic physics and hoping someone can help If i've got the wrong forum, please feel free to move this post. I'm designing a robot which resembles this one...
View ArticleWhy x^2 for PE?
Hi all, I notice the patterns such as v = 0.5at^2 and PE(spring)=0.5kx^2, etc...but, all examples I have seen show the slope (acceleration, or the spring constant, k) as being a 45 degree angle. Thus,...
View ArticleWhy use a batting glove?
Batters swear that batting gloves improve their performance. From a physics standpoint, why is this? My impression is that low friction between the bat and the hand causes more slipping during the hit...
View ArticleLinear Dispersion
How to find the linear dispersion of a Direct Vision Prism with given parameters?
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Thermodynamics: Convection and Industrial PC Heatsinks
Hi PhysicsForums. I have a question. I was looking through a manual for an industrial grade PC, which is fanless, with the CPU mounted directly onto the chassis which is practically one large heatsink....
View ArticleHow to deduct the gradient in spherical coordinates?
http://en.wikipedia.org/wiki/Gradien...al_coordinates which formula do we apply to get the gradient in spherical coordinates?
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