Classical Physics

Hi there, I have a question about opening a can of juice (for instance, pineapple juice) by puncturing the top end on with a knife. While I think I can guess why you have to make 2 holes on opposite sides of the lid, instead of just one (because two holes will allow opposing air & liquid / current flows, create an imbalance, finally pushing the juice out... 1) what exactly happens ? 2) how come making, for instance, two inch-long slits side by side on the lid, works too? Wouldn't the juice be coming up against air pressure pushing down in almost exactly the same direction? How come this works but having just one single ridiculous looking 2-inch slit wil…

I would like to know what happens to light as it focuses through a lens. If the example of looking at a blue star through a telescope is taken. Would it be correct to say all of the following? The density of the photons increases The frequency remains the same The amplitude of the light increases Thanks in advance for answering my questions regards Johann

can anybody explain what is a positive clipper?

if you have a horizontal slope that is> then 0, how would you use that slope to calculate to calculate a value for g (gravity)if you have an angle theta and a percentage of error and you already know the acceleration? Any help would be appreciated thank you.

Dear Forum, I have run across a very interesting machine that I was wondering if someone might could comment on. It is a version of the Sterling Engine, that uses a turbine instead of a piston. They have just completed phase I testing, and say it was successful. Here is a link: http://www.kendersolar.com/ This describes the technology: http://www.kendersolar.com/index.php/The-solar-technology-of-the-Kender-Engine-Phase-1.html They claim that the energy extracted by the solar panel produces more energy than what it takes to drive the compressor to circulate the helium, and results in: "The system produces 39 kW of power (47 kW by the turbine, less 8 kW …

I understand that connecting identical batteries in parallel will increase the overall battery's capacity. But what about: 1) If the batteries aren't identical? Say one is 2V, and the other is 4V. What will happen? Is there an equation to calculate overall emf? 2) If the batteries do not have negligible internal resistance? That is to say, e.g. each battery have internal resistance of 1 ohm. If you connect two of them (identical) in parallel, the overall resistance of the battery will become 0.5 ohm. So does the current in the circuit increase due to decreased overall resistance?

Assuming the solar system began as a single, undifferentiated cloud of energetic matter, it is strange that the cloud congealed into multiple gravity wells. After all, if a center of gravity was emerging within the cloud, why wouldn't the heaviest matter sink to the center and cause a single gas giant to form and eventually ignite into a fusion reaction (star)? I have read that the sun has supernovad in the past and this is perhaps how the heavier materials for the planets emerged from it. But why wouldn't the matter that emerged from an exploding star simply fall back into it? Is it just random chance that certain bits of matter did not attain escape velocity but yet…

I'm trying to figure out why the Brownian Ratchet fails as a violator of the second law of thermodynamics. The pages I've read do not make any sense to me. Can anyone explain it to me in somewhat simplistic terms? I'm only a few weeks into my Thermo class. Thanks.

http://en.wikipedia.org/wiki/Orders_of_magnitude_(force) The wiki article says that the force of light on earth from the sun is 570 MegaNewtons but I was wondering what this actually means and if there is any practical applications or useful information we can gather from this? The same article says the force from the space shuttle equals 1.8 MN at lift off and 570 seems a huge number yet I dont feel myself being crushed or incinerated when I go out in the daytime. What's the actual meaning of this expression. I assume it has some application in solar energy but i really dont understand what the expression means? could someone explain? Cheers,

Why does laminar flow occur at low velocities and turbulent flow occur at high velocities? I'm trying to understand it in terms of flow over a cylinder and adverse pressure gradients but I can't understand why an object moving at a higher velocity would experience a greater adverse pressure gradient than one moving at a slower velocity. Thank you!

Hi. In some other forum, a beginner asked how to run a domestic clothes dryer from batteries to save in electrical power , and responses were of course, to discourage such by multiple solid reasons. I suggested as alternative to make a 'closet' with the clothes hanging and force fan-air flow, no heat added. It would take much longer time, but... Would that electric fanning take much less energy for a much longer time ending in a not-worth-it alternative than a several kilowatts for only a couple of hours domestic clothes dryer ? In other words, would indoor clothes drying need to use the same amount of energy no matter what the method ? I do not think so…

What are the limitations of classic mechanics and which are its differences with quantum mechanics and relativistic mechanics?

Hello folks, first post here and hope I'm not being cheeky, but looking for a scientific answer to a domestic question. I have a domestic plumbing problem, 'Get a plumber' I hear you say'..... well, I have and he's stumped too. I'm an engineer by trade, and I'm sure there will be a scientific answer, but not my field. OK, here's the problem. I've enclosed an image of a hot water cylinder that is heated via a heat exchanger coil through which flows hot water from the boiler, ie the water in the cylinder is not directly heated itself. The water flows through the coil using convection, or so I'm told, and it is NOT pumped. Apparently the lighter hot water rises, the …

If energy can not be created or destroyed then what happens to the energy of 2 photons when they destructively intefere with each other?

So I started connecting some dots, and got lost. Work=Force x Distance. Of course. Force = mass x acceleration. Of course. Acceleration must be non-zero in order for there to be a force present. So imagine you're moving a box across the floor. You get the box moving, and from that point on you move at a constant velocity. The constant velocity indicates there is 0 acceleration, if there is 0 acceleration then 0 force is being applied. But that would mean that there is no work being done. But there must be work being done since the box is moving over a distance. How am I tripping up?

One broadly accepted concept in electronics is Michael Faraday’s notion that the entire charge placed onto a conductive body is to be found upon its outer surface. I agree with that notion and would like to suggest a mind-experiment for others who share that understanding. An electrically isolated bucket capturing negatively charged rainwater falling from the sky would store all excess electrons upon its outer conductive surface. They would have migrated there from within due to mutual repulsion. Hence, charged particles would have traveled from where they had been to where they were going. Therefore the entire physical host could be viewed as a body that presented t…

I thought to go underwater 100 m below water level and there inflate a leather balloon, volume 1 m3, theoretical work required would be: Po Vo = ro g h Vo = 980 000 Joule where Po pressure 100 m below water level Vo leather balloon volume g gravity acceleration ro water density h water depth ( 100 m ) Then, I let the balloon go and, pushed by Archimede force Fa, it goes up to the surface, theoretical work done by Archimede force to bring the balloon to the surface will be : Fa*h= ro*g*V*h = 980 000 joule We did not violate energy conservation, That's good ! I thought to go back to 100 m below w…

Hi. If a sealed glass container filled with salty water sits on a highly charged positive plate, and on its top a highly charged negative plate is placed; would the solution ions migrate towards the plates, leaving a leaner solution at the centre ? Sort of a glass dielectric Leyden jar...

E=mc^2 where E=energy M=mass c= the sped of light so the equation is really E=M*C^2 and sense we know what C is why do we put it to the second when we can just figure out what C^2 is and make that the constant? why not just put the value in the equation from the start?

would it be possible to look back at the earth through refracting of gravitational lensing. I'm not part of the scientific community, but I'd like to know if that's possible in any way. With all the massive gravitational fields in this galaxy maybe it could be a possibility to see a picture of the planet millenia ago?

I recently put on a pair of shorts that I had recently worn, and felt something in the pocket. I reached inside and pulled out a dime that was bent in the middle. I tried to bend it back with my fingers, but this is impossible for anyone but a member of The Power Team to do. I then inspected the coin for signs of tool marks and found none. The dime does not appear to be misshapen other than it is bent. I was wondering if anyone had any ideas how a coin can be bent without the use of tools and no signs deformity are present. My only other thought is that it got hot enough in the dryer to cause it to fold in half. Any ideas?

does the color of a laser decide how powerful it is? would a 1 MW red or IR laser be less powerful than a 1MW blue or violet laser or even ultraviolet laser?

There is air ionizers for several uses and claim some effects, but would like to know if negative ions are emitted from pointy needles exposed to ambient air as in some electronic gadgets sold, by negative or by positive high voltage. (Believe negative); what happens if the high voltage on the pointy needles is alternating ? What happens increasing the AC frequency to several KHz ?

what is mean by electric constant? electric constant = 1/(magnetic constant * speed of light) please explain this equation. why we need electric constant? whats the use of that?

Here's my question: imagine a ball rolling towards a brick wall. It hits the brick wall, and stops. It has lost its kinetic energy, right? And change in kinetic energy is equal to Work. But work also relies upon force being applied over a distance. So what I'm thinking is that there has been a nonzero change in kinetic energy, but because no change in distance occurred, no work was done. But that would violate the idea that the change in kinetic energy doesn't equal the work done. How is that possible?