# Tagged Questions

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### Containement system of a nuclear reactor: role of the water moderator

In a modern nuclear reactor for example a PWR there are multiple containment systems which prevent the release of radioactive material into the environment and shield the environment from the ...
344 views

### How does a force on electrons produce a force on a metal plate

In a paper from Cadwell Magnetic damping: Analysis of an eddy current brake using an airtrack about eddy current brakes the author explains the effect qualitatively as follows: When a ...
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### Electric current streamlines in induction cooking vessel

I am looking for a plot of the typical streamlines of the electric induced currents ("eddy currents") in a induction cooking vessel. How can one theoretically predict the streamlines? How is it ...
297 views

### Force of electromagnet on piece of iron

I can find equations to give the force of an electromagnet on a piece of iron when the iron touches the electromagnet. But what about when the iron is some distance from the electromagnet? ...
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### Can an induction coil heat two layers of metal?

Imagine we have an induction coil which is strong enough to heat a sheet of metal. We can put a sheet of ferromagnetic metal close to the coil at distance $h_1$, and it gets heated to temperature $t_1$...
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### If layers of insulation are continuously added to a heated object, will it continue to be better insulated?

If you were to keep adding layers of insulation to something, like blankets to a person, would each blanket continue to improve the insulation? Or do you reach some point at which the next blanket ...
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### Wavelength comparison of two waves

Is there any non-digital (naturally existing) mechanism to compare two or more waves in such a way: ...
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### What are the applications of Gauss's law in technology? [closed]

Freshmen physics textbooks use Gauss's law plus symmetry to calculate the electric field. I was wondering if this method of finding the electric field using a symmetry is used in real applications in ...
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### Formula for a ball rolling down an Inclined Plane

Suppose we set up an experiment where we have an inclined ramp, and a spherical basketball. If we were to assume the ball to be perfectly round, and rolls down in a vertical manner and the situation ...
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### What could be some applications for a highly compressed magnetic field?

If you had a powerful electromagnet in the shape of a hollow sphere in which the top and bottom halves are the opposing poles, what can the magnetic filed at the center of the sphere be used for?
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### What are the applications of delta function potentials?

Are there real applications for using delta function potentials in quantum mechanics (other than using it as an exactly solvable toy model in introductory undergraduate quantum mechanics textbooks) ?
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### Conservation of angular momentum in helicopter

I have a small RC-controlled toy helicopter with removable tail rotor. Suppose I remove the tail rotor, hold the tail with my hand, start the rotor until it moves with constant angular velocity and ...
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### What is the difference between an accelerometer and an inclinometer?

When looking through papers for a controls project I found one that seemed to be referencing the fusing of sensor data from an inclinometer and an accelerometer. I always had thought that it was ...
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### Magnetic flying engine [closed]

I invented a flying engine moving entirely by magnetic forces (such as the force related with magnetic field of the Earth). See http://porton.wordpress.com/2011/12/23/magnetic-vehicle/ The question ...
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### Is chaos theory essential in practical applications yet?

Do you know cases where chaos theory is actually applied to successfully predict essential results? Maybe some live identification of chaotic regimes, which causes new treatment of situations. I'd ...
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### Are quantum mechanics calculations useful for engineering?

I heard it's is pretty tough to get results for more than a few quantum particles. Are quantum mechanical calculations useful at all for any technology that is being sold? Or do they use quasi-...
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### Eliminating IR light reflection perceived by a steep viewing angle

I am having a problem with reflection on an acrylic surface, in the IR part of the spectrum. This reflection is interfering with an algorithm that looks at objects, as it makes two show up when only ...
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### Electrodynamics textbooks that emphasize applications

Please recommend undergraduate-level textbooks on electrodynamics which emphasize practical applications and real life examples. Please describe the book's level and contents and its intended audience ...
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### Do multiple permanent magnets aggregated together approach the same strength as a single magnet of the same size?

Here's an applied physics question. ;) If I buy some cube or sphere magnets like these, can I aggregate them together to create a stronger magnet (almost as strong as a single magnet)?
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### Real world examples for projectile thrown upwards or downwards

I am preparing a physics course for high school about projectile motions. If a projectile moves with initial velocity $v_0$ in the gravitational field of the earth, the equation  s(t) = 1/2 g t^2 ...
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I've come across an interesting question in the course of doing some exam review in a quantum mechanics book and thought I'd share it here. "What must be the frequency bandwidth of the detecting and ...
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### Additional accelerating force during take off of a rocket?

During the take off of a rocket, the exhaust produces some pressure below the rocket, which gives an additional force. How large is this force in comparison to the force produced directly by the ...
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### Applications of recoil principle in classical physics

Are there any interesting, important or (for the non physicist) astonishing examples where the recoil principle (as special case of conservation of linear momentum) is applied beside rockets and guns? ...
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### What are typical values of the critical thickness of insulation?

As most people who've had any elementary heat transfer course are aware, when insulating a pipe, wire, etc, there is a critical thickness for the insulation below which it causes greater heat transfer ...
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### Are there any practical applications of the uncertainty principle

I believe GPS works because of extremely small time differences between the satellites. Because of how small the time differences are, it needs to take into account gravity's effect on time. ...
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### Phenomena which are incorrectly declared as resonance phenomena?

In standard college physics text books, high-school books and popular level physics books, the collapse of the Tacoma Narrows Bridge is often taken as an example of resonance. However a more detailed ...
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### How can I measure the physical properties of a metallic string?

Metallic strings exist in different kinds but I would like to measure for a metallic string: the section/geometry along its length, to a precision of 1/100 mm its elongation when a tension is ...
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### Why should optical fibers be thin?

What are the reasons that optical fibers have to be thin (small radius of the fiber)? Is there a good picture which explains this in detail?
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Why do optical fibers usually have a cladding? Ok, if you put make a bundle of optical fibers this prevents that light leaks from one fiber to another fiber in contact. However, are there other ...
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### How does the Kinect device work?

Some explanations of the device base it on a simple echo of light: "The camera transmits invisible near-infrared light and measures its “time of flight” after it reflects off the objects. Time-of-...
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### Practical applications for a Bose-Einstein condensate

What are the main practical applications that a Bose-Einstein condensate can have?
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### Practical uses of antimatter in the present

I recently found out that a PET scan stands for a positron emission tomography. Are there any other practical uses of antimatter in the present?
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### If a vehicle is rolling down a hill, will its speed depend on the size of the wheel?

If I am sitting on a skateboard and travel downhill, will the velocity depend at all on the size of the wheel? The skateboard is only powered by gravity. There are a lot of variables to consider. ...
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### How do I figure out the effects of wind on flight?

For a school project, I'm trying to make an automated flight planner, considering mainly the differences in flight paths according to wind. Now I've heard that flying with/against the wind affects ...
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### Tire speed dependent friction

I have an old, non power steered car. When the car is stationary, the steering wheel is really tough to move, but as soon as I gain very little (0.5 kph or so) speed, the resistance is dramaticly ...
512 views

### Law for tap water temperature

I was wondering if anyone put together a law to describe the rising temperature of the water coming out of a tap. The setup is fairly simple: there's a water tank at temperature T, a metal tube of ...