Physics

I know an AC current can be rectified to a DC current with a diode bridge, but does the magnitude of the voltage and/or current change? If so, how. For example, if one had an AC current at 2 A and 12 V, and one converted it to DC, what would the current and voltage of the new DC current be? Btw, let's assume that the process is 100% efficient.

Hello, I am wondering if anyone has heard of anything that can be used as a heating element , yet is transparent. Like transparent metal for example ? Glass as we all know is a poor conductor of heat ! But there has to be something else Thanks

From my lab this week, I analyzed that the projectile motion is independent from the mass of the object and that it's not a factor in any equation for projectile motion. I said this based on my lab results. But I find it difficult to believe that it's true with my eyes. I don't know.. I just feel like heavier object, like car, will have less steeper projectile motion than soccer ball. Can anyone tell me if I'm right (and that my eyes, just like in other scenarios of physics, are deceptive)?

When an atom becomes an positive ion, magnetic field should be able to repel it. But my question is, is this possible? First of all, if magnetic field can change the direction of flowing electrons then for it to change the direction of ion should be possible. But i think the main problem is how far the ions will travel depending on the strength of the magnetic field. P.S. it will be great if anyone know any equations that might help Merged post follows: Consecutive posts mergedP.S. when I say changing the direction of flowing electrons, I mean when electrons are traveling through air.

I have problem understanding Newton-metre unit (or should it be written in all-lowercase style: newton-metre? Or newton-meter perhaps?). I don't have the problem with the unit itself, but with the way the unit is written: N m (or even with a small central dot in between: N*m). According to Wikipedia, the newton-metre unit has a space between 'N' and 'm'. But this would indicate the 'dot product', wouldn't it? It seems to me that it would be better to write the Newton-meter unit all compact: Nm. This way 'Nm' is clearly a unique symbol, and not a compound unit. If you insist, I might accept: N x m (indicates vector product). Now, in my software (Math-o-mir) I i…

/i was traveling today and having nothing better to do I was thinking about speed. Speed is represented by distance divided by time, meters divided by seconds: the amount of meters traveled in one second. The reverse (inverse, opposite) would be the amount of seconds traveled in one meter. It is the amount of seconds needed to travel one meter. Which is still a speed. Just as if the inverse of speed was speed. Or am I completely wrong?

Planets Orbit Not Because Of Gravity Energy But Because Of Griff Energy... Why does the moon not fly off? Why do astronauts float in space? Objects fall to earth at the same speed?, All of this does not make sense. If astronauts "float" in space, then there is no gravity in space. So whats the moon doing? I thought there is no gravity in space? Very confusing It may be that each planet or moon is held in a gravity ring and between these rings is no gravity. I doubt this is true. Or is there such a thing I would like to call "Griff" in our universe that keeps things draging along such as the moon orbiting the earth while the earth orbits the sun. (G…

In a physics discussion when during lab times, we had to measure the speed of sound forming a standing waves in a long tube filled with water, by adjusting the height of the water in the tube. Now the frequency we produced was directly from a tuning fork, not some machine, so after we tap on to the tuning fork, we put it above the tube and listen to the loudest sound it produces. My question is how on earth do you get the uncertainty values for the tuning fork or the frequency? i mean i know the other uncertainty values such as the wavelength etc... you can calculate them through the uncertainty of the height of the water column on the tube. But i have no idea how to…

Ok..so I'm in physics and having an argument with my teacher about inertia. He says that in a game of tug-of-war that it has nothing to do with the force, because newtons laws says that its equal no matter what..that part i get and agree with..well there's no agreeing it's correct..anyways so he says the only way to win is to have more friction than that of the other side..this is the part where the arguement comes in. Ok..does inertia affect this, or is it really just ALL friction. I agree with him, but I do think that inertia has something to do with it. -Matt

Purely out of interest, does anyone here know what this equation- extracted from an episode of The Big Bang Theory- is about? (other than nuclear physics). It gets sheldon cooper (despite being fictional) stuck, and he's meant to be genius. From that, and that alone, I'm assuming it's something pretty complex?

If you make a string that's attached at both ends vibrate, it will emit an almost imperceptible sound. The role of the soundbox is to amplify that sound. My question is : where does the energy required for the amplification come from ? You surely don't add any vibrational energy by attaching a piece of wood. Is it just that the soundbox dissipates the string's energy faster, so that we hear a louder, albeit shorter note ? Thanks for your input, McCrunchy

What is the difference between a point charge [math] q [/math] and a test charge [math] q_0 [/math] ? When dealing with electric potential, my book gives one equation when dealing with a test charge: [math] V = EPE/q_0 [/math] and one when dealing with a point charge: [math] V = kq/r [/math] Why is there a difference between the two?

In kidsgeo they write that as air is heated it expands becoming less dense, and as a result, lighter. http://www.kidsgeo.com/geography-for-kids/0070-adiabatic-temperature-changes.php But why is that really?

Hi I wonder if you science guys can see if this works OK if you guys know that The maglev train moves on magnetic levitation but I wonder if this process can be reversed... in such a way. I was thinking that this method may make a lot of things faster.... like Tankers?

Hello. I need to know if there is ANY way that a magnet can be made to PUSH metal away, instead of attracting it. Thanks.

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They are higher than most things in suburban areas, and they have those giant towers holding them up, and they are all over the place. One would figure that they get struck by lightning often. So, what happens when..... 1. One of the towers gets struck? 2. One of the lines gets struck? Also 3. Why don't those poles on top of sky scrappers ever melt from being struck? 4. How does a man get struck by lightning and not get burned? 5. How much more likely am I to get struck by lightning if I stand directly under a very lightning active thunderstorm in the middle of a flat and wide open field with a 20ft pole in my hand sticking int he air? 6. Will …

Hello everyone, I have got confused with this. Normal the friction force acts to cancel the force. If I travel with 10 N force and friction is 5N, I travel at 5N. Why is that when you make a turn they don't create a net force, but act as separate forces? EDIT: I suppose the tires are turning outward all the time in different directions to keep it on the road. when you have turn in the circle outward force is little bit greater than friction I think, which makes the car turn in the right direction, before it is stopped by friction again.

I've been curious about this lately so I wanted to ask a question for the folks here. Who among you consider themselves to be open-minded physicists? For those who consider themselves to be open-minded can you think of a concrete example? Please explain what it means to you for a physicists to be open minded? Thank you all in advance. Pete

Hi, I am working with a couple of highschool students on a physics project their class is doing. They have to construct a yoyo that will fall a distance of 2 meters in the GREATEST amount of time. Mechanical friction cannot be used as a means of slowing the yoyo down. The maximum allowed mass is 1000grams and the maximum diameter / length is 20cm. We came up with a square shape and a thin rod in between. We acheived a time of about 3 minutes. Now today one of the students talked to me about the 'competition'. Apparently a rivaling group claimed to have gotten the yoyo slowed down to 45 minutes over the 2 meter drop. I have thought about how this is pos…

I don't drink coke, but I should imagine they are quite sturdy. I wondered how a lot of this is done but specifically the coke bottle trick. Is it plausible that is having so much strength against force from the outside a coke bottle is week against force from the inside? Much like how an alligator can bite closed with enormous force but can't resist the force of a stout rubber band holding it's mouth closed when attempting to apply opening force.

Why does windy weather seem to impact digital TV signals? Since we went to digital signals I have noticed the weather has a big effect on Digital TV signals but I can't explain why wind on a clear night seems negatively effect TV signals?

So E = mc2 right? That means that matter can be converted to energy, and visa-versa. What particles does this apply to? It must apply at least to electrons, protons, and neutrons, which in turn means it applies to quarks. Now what form does this energy take once an electron or quark is converted to it? Would it be a photon? How many photons per particle? This must mean that electrons and quarks can be converted into photons and visa-versa. Am I right?

As mentioned in the title I want to be able to make an electric heater coil that is capable of producing temperatures of 350-400 degrees farenheit with a simple 12 volt car battery? Thanks for the help.

EMR, electromagnetic radiation is emitted from the Sun? EMR is made up of a visual spectrum been several different wavelengths and also has invisible wavelengths, such has radio waves? EMR as an whole, a collective, with no interference of its natural state, is transparent? A light bulb , a naked flame, a flashlight all emit a form of EMR? Light is apart of EMR and is said as single particles are known has a Photon? Photons and emr is mass less and do not have a Physical body? EMR has potential energy? Whenever you can see, EMR must be present? EMR is always isotropic from the source? EMR is apparently present in th…