Classical Physics

In space, is there a physical pressure? http://hypertextbook.com/facts/2002/MimiZheng.shtml Is this link accurate? If in space, sweat can not even escape a human body, which is a physical pressurised body , which has acting force on the sweat to force out of the human body, why can sweat not escape? unless there is greater pressure? It does not make sense to me I can not understand why is it not P=F/E? And is it so hot in space, in sunlight, because there is no thermal barrier i.e Earth's atmosphere to protect you?

I've recently been doing studies on reduction of drag and skin friction for a project and I'm curious about a couple of things. First, I found an academic paper on the reduction of skin friction for sharks. Their incredibly complex skin seems to disperse water in a way that allows sharp maneuverability and reduces skin friction as much as 8%. This reduction however, can't go said without considering the speed they function at which is usually 50 km/h. (pretty slow in comparison to a sailfish of over 100 km/h) I'm sure at higher speeds the skin friction could vary... You would wonder why I'm not asking about the sailfish but actually the V-shaped protrusions on thei…

has any optic experiment been done within the context of the casimir experiment? That is, as the plates near each other and the gap narrows so as to interfere with VP resonance, has anyone sent light through the narrow gap to see if light is affected in correlation to this particle behavior?

I will get this out of the way for you. I am an extremely inquisitive idiot with a thirst for knowledge about how things around me work. I am hoping my very BASIC questions don't p!ss you off, but I can't seem to find the answers I am looking for. Torque. Fishing reels. With my VERY limited knowledge, it looks like torque should decrease as the diameter of the reel spool decreases, no? I know there are variables, like drag and line pound test, but practically it seems like the torque increases as the diameter of the spinning spool decreases. A long running fish will peel off a lot of line and every fisherman in the world has been guilty of increasing the drag a …

Can we determine the type of sound produced on collision of two objects without actually hitting each other by study about objects properties............. As we know different types of materials collision produce different type of sound.

I am not sure if I understand how forces work during hammerthrow. From my understanding athlete works with Fmuscle force on a ball and rotate it and a ball works with equal opposite force on an athlete causing rotation in a opposite direction. The mass of athlete is greater than the mass of ball so athlete rotates with ball in 1 direction(Fmuscle direction). Does it mean if ball would be heavier(more massive) than athlete, the athlete could not rotate it(even if strong enough to move it) ?

[math]\vec{F}=q\vec{v}\times\vec{B}[/math] [math]\frac{d\vec{F}}{dq}=\vec{v}\times\vec{B}[/math] [math]\int\frac{d\vec{F}}{dq} \cdot ds=\int(\frac{d\vec{s}}{dt}\times\vec{B}) \cdot ds[/math] from here, I went about it two different ways: 1.) Here I assumed everything was at right angles and got rid of all the vectors and vector products [math]\varepsilon=\int \frac{ds}{dt}B ds=\int \frac{ds}{dt}B \frac{ds}{dt}dt[/math] By u substitution [math]u=\frac{ds}{dt}, du=dt[/math] [math]\varepsilon=\int B(u^2)du=\frac{Bv^3}{3}[/math] where v = ds/dt That was the first way i went about it, but i didn't feel any closer to Faraday's law. 2.) Here I left the vectors alone …

(I will use abstract approximate 1 dimension positions for example) I mean let's say I stay at position x=0, now I move my arm forward(positive value change), my arm is at position x=5 any my body is still at position x=0 cause friction of my body and ground is much greater than my body movement backward (caused by moving arm forward). Now let's say my arm weight 100x more than the rest of my body(it is just example), when I try to move my arm forward will instead my body be at position like x=-5(backward movement) and my arm like x=0 (or a very small positive value) ? (It seems a bit strange - I based it on understanding that less massive part moves much more than more …

So here's a fairly basic question. I understand that rocket thrusters work by expelling hot gas into empty space, which results in motion in the opposite direction. This is because of the equal and opposite reaction to that force right? In my mind it's completely unintuitive that a thruster would work without pushing against something. So is this equal and opposite reaction explanation all there is to it? Is there a way of breaking this down into something that could be understood more intuitively or is it just a 'brute fact' that I need to accept?

Hi, I was hoping to get some pointers/ references for the following: I'm trying to learn about the force that an electron experiences while in a conductor. When bound to a conductor, it's essentially in potential well. My goal is be able to model this potential well to manipulate it. I'm trying to get an electron to physically leave its conductor but i don't want to just blindly "do it," i want to understand it. Thanks in advance

Measuring gravity is deciding whether gravity is a wave or a particle or a gravity wave or a graviton first of all. By placing a pendulums and magnet that swing the pendulum back and forth on planets or moons with varied gravitational forces then you can deduce that the pendulums swing at different rates or speeds assume that because of the varied rates you can thus have acceleration you can use the equation to tabulate the weight of an object. In this experiment you would have to land a pendulum and magnet on all the planets to prove the theory? Or could you experiment with simply knowing that 9.8m/sec2 divided by 1/6 the gravity of the moon is the rate of the speed of g…

Hi can anyone help me understand how gravity and magnetism adhere to the laws of energy conversion and conservation. To this layman they appear to break those laws. Let me share my miss-conceptions. A magnet (or gravity) appears to have a constant force (attraction and repulsion) without any energy conversion. My understanding is any force must equate to some kind of energy. How is this so? So where is the little engine hidden inside my magnet? WallyZ

I was looking at a wikipedia page about the sound barrier, and thought a question that there was no answer to in the page. If you had a liquid that was about to be a solid if you put a little more presure. then you set an explosion would the resulting wave be able to go faster than the sound barrier? The equations don't account for phase changes. Something really interesting to try is to see if you can have a liquid close to being a solid with a little more pressure, and set it up to take the pressure away afterward. Could you do this with air?

Hi All, Newbie to this forum. I did a searxh on 'scientific forums' and this one looked quite likely to answer my query. I hope you can help........ A friend and I were discussing a theoretical situatuation where two USB power packs (the type that act as emergency chargers for phones, iPads, etc) were connected to eachother in such a way as they could both draw power from the other and could both charge the other. (It must be possible to connect power packs in this way, as a single power pack can draw electricity from the mains whilst providing power to a device via a USB charger, for example.) We assumed that the power packs would start off at 100% full, bu…

Is this an effect that can be explained? The bottom of the slinky always hovers until the top reaches it... https://lh6.googleusercontent.com/-caaugfzCvlg/U8602uHWxVI/AAAAAAAAFuM/pgAkBL9NzWM/w280-h314-no/dada.jpg

So I'm confused on what is the actual cause of gravity because I heard that gravity is caused by the curvature of space time from the mass of objects. I also hear that gravity is cause by a massless particle called a graviton. Which one is it or do they both play a role in the cause of gravity.

Many posters here argue against a proposition on the basis that it is 'non mathematical' rather than against the merits or demerits of the proposition itself. So who can offer a mathematical definition of thermodynamic reversibility? The only attempt (not even wikipedia tries http://en.wikipedia.org/wiki/Reversible_process_(thermodynamics ) that I can find is in Callen and that fails counterexamples in both Atkins and Carrington. Remember any proposed definition must be applicable to any conceivable set of circumstances, not just specially constructed ones.

It is a pretty lengthy video, and has me pondering on things.. BLACK HOLES - WHAT ARE THEY? (Documentary) Science/ http://www.youtube.com/watch?v=at19-lv4Cpw From what I understand the issue is How Does Quantum Mechanics and Gravity live together?? I ask why do they need to?? What would it prove? On another note, how on earth did Albert Einstein in his time know about these?? Could he have not known he was that smart?

Can someone explain the profound device displayed ? I'm currently working on a new project that involves anti gravity and is in need of assistance for the mechanism's displayed in this device. There is a video on youtube ( Anti gravity magnetic field ) and I understand the device involves electromagnets and needs to be plugged in. Any explanation on the placements and magnet types would be much appreciated and once my project is done i'd be happy to share it with you guys (:

Would the trajectory of a pellet shot from an air rifle be different whether using the same pressure of various gasses, for example charging with air vs. a heavier gas such as carbon dioxide? That is, would the heavier gas impart more energy to the projectile?

If I would hit wall(with fist) very very hard (I mean with strength drastically greater than human can possess) and that wall wouldn't crush would I move backward (like few meters backward or other noticable distance) ?

Dear Sir/Friends, I was just observing the functioning of a wind mill to generate electricity(Conversion of mechanical energy to electrical energy). If so, my question is , Can't we generate electricity from fan while it is running so that the mechanical energy while the fan is rotating can be converted into electrical energy ? Please correct me if iam wrong ... Thanks & Regards, Anish

Question: Is this a satisfactory formula for the electrical interaction of 2 electrons at speeds << c? K cos(X) Vv/r^2 – Q^2/r^2 Where V is the velocity of the causing electron v is the velocity of the effected electron r is the distance between them Q is the charge of the electrons X is the angle between the direction of v and the plane of the direction of the cause electron and the position of the effect electron. (The alignment with the flux) K is the constant to make the units come out right. I will answer it myself. NO. It at least needs…

I was thinking about how astronauts aboard the ISS poop in zero g. I creatively had the idea of an axis on the ceiling of the toilet (I know there is no up or down, but you get my point). The stall would be manually spun by other astronauts (to save power) and the poop would naturally fall. That wouldn't be possible, obviously, because it would make the entire space station spin a little bit too. I was thinking if the bathroom could be temporarily detached from the space station. In that case it wouldn't transfer energy to the station. However that would be risky because there is a chance you'd fly away into space while pooping (that would actually be pretty funny, wh…

For the people who are familar with continuum mechanics: How I can derive a stress tensor T for a chocolate dependent on - Cauchy-Green deformation tensor E - Strain rate tensor D (is objective derivative of E) - The time where the chocolate is exposed mechanical loads or temperatures (denoted by t) - The state of the chocolate (whether it is solid or liquid) - etc.? I am very familar with continuum mechanics, I know how to derive material models for viscoelastic, plastic or viscoplastic continua. But chocolate seems to be more complicated than these, because chocolate will undergo a phase change if it is chewed in the mouth. I have to use diffusion equatio…