# All Questions

134,985 questions
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### What is the link between the rotating wave approximation and the algebraic representation of a dynamical system?

In analyzing a system of two coupled oscillators, I noticed a rather interesting correspondence between the so-called "rotating wave approximation" (RWA) for solving differential equations and the ...
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### Why can I not conserve kinetic energy in the following case? [on hold]

For the 2nd part of the question, if I conserve angular momentum about the centre of mass of the rod I get one value, and if I conserve kinetic energy of the rod and ball system before and after ...
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### why a car with very high speed topples away from the center of turning when it is cornering? [duplicate]

If a car is turning to the right with very high speed, why the car will topple to the left and cause an accident?
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### Where's the Database in Grover's Algorithm

I am a little confused by parts of Quantum Computation and Quantum Information by Nielsen and Chuang on Grover's algorithm: Grover's algorithm searches a number of quantum states for a "marked ...
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### Why the quantities are dimensionless in curves plots?

In a lot of plots they use dimensionless quantities, why really we don't let quantities in their physical dimension and plot the curves normally.
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### Wave equations calculations involving crests, wavelength, frequency, period and time, crests that pass you per second while standing [on hold]

How to calculate the number of crests given wavelenght and period
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### Can a light absorbing bulb-like thing be made?

A bulb emits light. So can a bulb-like thing or anything be made such that it absorbs all/most of the light when turned on? For example, when room is dark we switch on bulb and it spreads light. Let ...
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### power calculation when subjected to certain load [on hold]

What is the power consumed by a battery whose voltage is $300$ V which has a capacity of $3000$ Ah? When it is pulling a load of $430$ tons at a speed of $10$ kph for a period of $10$ minutes. In ...
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### Normal Force on an object on the earth’s surface

If a body is on the earth’s surface at equilibrium, the forces acting on it are gravitational (by the earth’s centre) and normal (by the surface). These balance each other and allow the body to ...
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### Intensity pattern in a single-slit diffraction

In a single-slit diffraction, what happens to the intensity pattern if the slit width becomes narrower and narrower?
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### What happens when the wavelength of light becomes as large as the observable universe? [on hold]

Say the wavelength of a photon became so large that it approached the size of the observational universe. Does something unexpected happen?
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### Mathematical formulation of quantum mechanics

I am reading a book on quantum mechanics, but it is difficult to understand. Quantum mechanics is roughly formulated as follows: Physicsl state is a normalized ray \$\{e^{i\theta}\psi|\theta \in \...
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### Nature of motion between comoving observers; What is the common time that they agree on?

This is a set of follow-up questions regarding this post. The following four queries are very closely related and needed to asked at the same place. Question 1 Is it really possible to regard the ...
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### Einstein's Theory of Relativity Time Dilation

My friend claims that this proves that time moves faster on a mountain than at sea level. He says that since both of these people start and end at the same angular position and are both traveling at ...
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### Is the magnetic force fully analogous to gravitation?

Superficially, the force between two magnets would seem to be fully analogous to gravity because each is the product of two factors divided by the square of the distance between the objects being ...
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### Combining two power sources to get voltage from one and current from another

For a project, I have to make a battery that output 5 V, 500 mA. However, each one of my cells can only produce 1 V, 80 mA. I can combine these cells in series and parallel to get the required ...
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### What is “quantized momentum transfer”, and can it account for the double-slit experiment?

In https://www.sciencedirect.com/science/article/pii/S0378437109010401, the author claims that the interference pattern obtained in the double-slit experiment does not need a wave description of ...
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### Prove from first principles that a guitar string will vibrate at a constant frequency

From experience I am aware that a taught string will generally vibrate with a constant frequency. I wanted to prove this by considering the relation of distance from the resting position, and its ...