Physics

i hope you dont mind an average joe joining in. i have some thought experiments and no one to tell them to .ive seen some intresting things here already. Anyway could somone explain to me why scientist keep using time in formulas to calculate theorys? i mean time is just distance right? i mean what passed objects traveled electron moved from here to there but what passed???? help

At the top of a rollercoaster loop gravity is sufficient to provide the necessary centripetal force, however at the bottom of the loop gravity is pointing away from the centre so other than the normal force (which I presume balances mg) where does the extra inward force come from which supplements the normal force thus contributing to the feeling of heaviness and keeps you moving in a circle? Thanks

what are induced electric fields? how can they be produce? how are magnetic fields and electric fields related to each other?

What is negative impedance exactly? According to this Wiki article, it is an "energy injection".. But I'm not sure whether the information is credible. http://en.wikipedia.org/wiki/Negative_resistance#What_a_negative_impedance_is

A student places a row boat in a swimming pool, loads the boat with a number of bricks, and rows to the center of the pool. Once there, the student carefully notes the water level, throws the bricks into the swimming pool and once again notes the water level. What had happened to the water level in the pool?

Hello, Does someone ask: what’s happened when the potential difference between electrodes in a electrolytic cell is lower then that necessary for electrodes reactions? According to actual definition of electric current, as a charge movement, in this case, the electrolytic cell should comport like a capacitor. The results of the experiments are completely contrary to actual theoretical prediction for solution and molten salts, as can be seen at: http://www.elkadot.com/chemistry/Electrolysis%20of%20Molten%20Sodium%20Chloride.htm http://www.elkadot.com/magneticity/Electric%20currents%20in%20solutions%20and%20charge%20movement.htm Can someone figure ou…

could a biodynamic ecosystem be used as/on a spaceship? like, if you had the whole spaceship{except for the engines and others}as a biodynamic ecosystem, water supply recycled to the fullest, food eaten, and reproduced, and basicly have a superminiature earth on/as a spaceship. if so, then we could actually live out of earth, pull some serious star trek. its engines could be something like laser powered, it doesnt really need to get anywhere fast. though it would be better. have generators on board, and at least more than a hundred people, becuase less, than mutations would eventually occur and the intelligent life aboard the ship would die, or become unlike any other hum…

A high fountain of water is located at the center of a circular pool as in the figure below. Not wishing to get his feet wet, a student walks around the pool and measures its circumference to be 25.0 m. Next, the student stands at the edge of the pool and uses a protractor to gauge the angle of elevation at the bottom of the fountain to be 55.0°. How high is the fountain? I did: 2(pi)r=25 r=39.27 m y=39.27sin(55)=32.17 m However i was wrong. Any advice.

A woman measures the angle of elevation of a mountaintop as 12.0°. After walking 0.80 km closer to the mountain on level ground, she finds the angle to be 14.0° (a) Draw a picture of the problem, neglecting the height of the woman's eyes above the ground. Hint: Use two triangles. (Do this on paper. Your instructor may ask you to turn in this work.) (b) Select variable names for the mountain height (suggestion: y) and the woman's original distance from the mountain (suggestion: x) and label the picture. (Do this on paper. Your instructor may ask you to turn in this work.) © Using the labeled picture and the tangent function, write two trigonometric equations rela…

when I close my ears by my hand . I hear a noise actually two different noises . one of them with different vibration -frequency- ( like something exploding) and other one has same vibration -frequency- it's more like ( toooooooooo ). any one know what are those sounds ? and I'm sorry if that was a stupid question

I need help with this problem. My teacher gave it to us but I'm not sure how to proceed. The tape in a standard VHS cassette has a otal length of 246m, which lasts for 2.0 hr. As it starts the full reel has a 45mm outer radius and a 12 mm inner radius. At some point during the play both reals have the same angular speed. Calculate the angular speen in rads/sec and in revs/min. Hint: Between the two reels the tape moves at a constant speed My teacher said we might find these equations helpful: W=R/R(f) W is angular velocity V=L/t πr^2=.5(πR^2-πr^2) I know I have to convert 2.0 hr to 7200 secs. If I use the second equation she gave then I …

In 1985-86 years I made a number of discoveries and several hundred inventions in the field of savings and production of super-cheap alternative energy. About hundred inventions I even patented or made a patent application. Among them: super-cheap in the production slow hydro-turbine with efficiency more than 98%, turbine with constant efficiency, turbine engine with efficiency 56%, steam engine with efficiency to 72% (today their efficiency it does not exceed 7%), the increase of the caloricity of chemical fuel en 2 and more times (that is equivalent to the doubling of world's supplies of coal and oil and gas), super-cheap variable-speed drive (automatic gearb…

If gravity has infinite range why do you feel weightless if you're traveling through space at constant speed? For example if I were traveling (in a space craft) at constant speed towards the Moon why would I feel weightless?

Hi, commonly crystal/solution boundary looks dark. Is that due to destructive interference at the boundary of the two mediums wih different refractive indices? As there are sharp crystal edges this pretty much resembles the behaviour of an optical wedge....or?

So i recently started doing research on how to make my own tesla coil. The design that i decided on is pretty simple- the main coil circuit consists of a power supply, a capacitor, an inductor with only a few winds, and a spark gap as a switch. the secondary is just a coil around pvc pipe with an aluminum bowl type of thing on the top (i havn't decided exactly what to do for that part). So figured out most of the details... a few things still evade me. I was going to use a 66 watt compact flourescent sawed off at the bulb linked to an old flyback transformer... Some sites i found say that the design i have works with a DC power supply like i described above and i don'…

I was looking up formulas for inductance of a coil with an air core and i found this one. L=(r^2*n^2)/(9r+10l), where L is inductance, r is radius of coils, n is number of coils and l is length of coil... what is length of coil? is it total conductor in the coil? also, i need to calculate resonance of an LC circuit. i got the formula R=1/2pi(LC)^1/2... does current or voltage affect resonance? does resistance?

Does a square have a greater moment of intertia? or a circle?

I hope the Mods don't shift this thread but I don't know where it goes. I saw a TV programme featuring an ex-Marine about the amazing array of weapons and military hardware held by the USA. He mentioned that there was a microwave weapon called the Active Denial System. This is aimed like a laser and can cause extreme pain in targeted individuals. It causes searing heat under the skin and forces pain receptors to give messages to the brain causes the person to move away quickly. http://www.globalsecurity.org/military/systems/ground/v-mads.htm However, I have been speaking to people who have experienced pains in internal and external tissues - stomach, chest …

In College Physics 7th Ed by Serway it states that the tangential speed of the surface of the Earth at the equator is 1700m/s!! Is this correct? I thought it was more like 465m/s.

It is known that when a gas expands it cools down. But why does the decrease in pressure cause the molecules of the gas to slow down?

Hello everyone, In this thread you can read about my favourite hobby, prehistoric iron smelting: http://www.scienceforums.net/forum/showthread.php?t=36160 During the last few years I've been running a series of experimental-archaeological iron smelts in order to find the best possible method for extracting iron from local bog iron ore in a historical context. Among the numerous problems that I've had to deal with, controlling air flow is one of the bigger ones. Here's a schematic showing a common furnace setup: Inner furnace diameter is roughly 30 cm. The front plate is rectangular, roughly 25 by 35 cm. The air inlet is 2-4 cm in diameter. Air sup…

A proton, and an anti-proton will collide to release both of their mass-energies, and c^2 is just considered a conversion factor. But is it possible c^2 represents something, why not? For example, a velocity of an object (like a quark) times the velocity of something else (i.e. electron), or the centripetal acceleration (m/s^2) of something times a distance (m). Is it possible to break c^2 down into something else? How is it described in special relativity?

What is the reason that it's colder at higher elevations? Is it because there is less solid mass to heat up at higher elevations?

http://discovermagazine.com/columns/top-100-stories-of-2008 enjoy ======================================= to narrow the focus to just physics, here are the top ten physics stories of the year according to Physics News Update http://www.aip.org/pnu/2008/split/879-1.html

It's possible this is already obvious in the math, but if so, I don't have the luxury of understanding equations on that kind of level. So here goes. I understand thermal energy always moves from a hotter source to a colder one. But logically, I would think it moves in both directions, but the hotter source moves faster and thus wins out. The same logic I would think applies to similar events like diffusion. It's possible my thought experiment is correct but popularizations, and the way it's taught in earlier schooling, makes it less intuitive, as if some unknown force were biased towards heat and equilibrium. Am I on track here?