# All Questions

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### Uncertainty principle-QM [duplicate]

I some trouble understanding the uncertainty principle. I understand most of the math derivation but not the physics. Is there any intuitive explanation of this idea, and why is the uncertanty does ...
0answers
53 views

### (1+1)-General Relativity

Goodevening everyone, my question is: What is the interest of studying the (1+1)dimension General Relativity? Can you explain please? Thank's in advance!
1answer
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### Force of water hitting a wall

If you had a 8" pipe with 500psi stream of water exiting it and hitting a wall at 90 degrees 8 feet away, what would the force of the water on the wall be? Thank you all. Non-mathematician.
1answer
34 views

### Projectile motion with air friction force/resistance [on hold]

We have to find the x (the distance, if you didn't know that then I'm not sure if you should be doing this problem) that the projectile travel during the time in the air until the time it hits the ...
1answer
31 views

### Is this possible to create a 1D or 2D thing in real?

We are living in the fourth dimension(time).So we can now travel through the third dimension. Now just imagine to make a 1 dimension thing, A line in real world. If I draw a line in paper with a ...
1answer
37 views

### A puzzler in induction and special relativity

Some reading I was doing jogged my memory about a puzzle in E&M that hit me back in my undergrad days, but I just let it go at the time and never found an answer. A pretty common undergrad E&...
0answers
30 views

### General relativity applications other than gravity

Do the Einstein field equations successfully predict/describe physical processes other than gravitational ones?
0answers
24 views

### Can orbiting a black hole 99.99% speed of light make other object with relatively fast clock travel faster than light, relative to me?

If i orbit a black hole, 99.9% speed of light, time for me is moving slowly, relative to me, planet earth is aging fast, and i have traveled 10 years into the future(relatively) in 1 second, suppose ...
2answers
52 views

### How is one element capable of radiating (almost) every wavelength?

Black bodies are considered as emitting all wavelengths. A incandescent light bulb has (nearly/almost) also the continuous blackbody spectrum near-perfect color rendition. In this bulb is only one ...
2answers
30 views

### Springs acting on a car

I am trying to solve a problem but I can't figure out why the answer comes out to be what it is: A man of 80kg enters a car and compresses the 4 springs of the car, causing a change of 1,2cm from ...
1answer
17 views

### Does resonator will always dampen the driving oscillator?

I was doing a question about resonance of sound box connecting to a tuning fork. It asks why the sound lasts for a shorter time with sound box than if the tuning fork is struck identically without the ...
1answer
55 views

### Intuitive analysis of gradient, divergence, curl

I have read the most basic and important parts of vector calculus are gradient, divergence and curl. These three things are too important to analyse a vector field and I have gone through the physical ...
1answer
41 views

### Such a huge mass for Higgs boson? And how can it, as a quantum, decay?

With a mass of 126GeV/c2 Higgs boson would have a mass slightly greater than a caesium atom. Isn't it too much? Wouldn't be in this way the ubiquitous Higgs field so dense to cause problems for the ...
0answers
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### How small can a sample size be of space to detect space-time curvature?

What is the minimal sample size of space necessary to detect space-time curvature?
1answer
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2answers
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### Moving of spin up and spin down electrons in a magnetic field

Suppose we have an electron in a conducting space, and now we apply a magnetic field. Now according to the right hand rule, the electron will have a circular motion in the plane perpendicular to the ...
1answer
71 views

### Constrained motion [on hold]

All speed shown are with respect to ground. Then we have to find the speed of block B with respect to ground. I tried it by two methods, but got different result why?
1answer
33 views

### Maximum range in projectile motion (elliptical path)

Elementary Newtonian mechanics tells us that if a projectile is shot at 45 degrees from the ground, and a downward gravitational field is acting on it, it will follow a parabolic path and achieve ...
0answers
26 views

### Buckling of elastica

The simplest equation for buckling of a beam is $$y''''(x) + \rho \, y''(x) = 0,$$ where $y(x)$ is the displacement from the base state and $\rho$ the ratio between the ...
2answers
27 views

### Why is the water still in the glass while rolling?

Pilot drinks glass of water while rolling the plane. The water stays in the glass, even if the plane is upside down. How is this possible? Why doesn't the water leave the glass, as it does when I ...
0answers
36 views

### Static vs Dynamic pressure?

According to Bernoulli's law, the narrower the tube where the fluid is flowing the lower its static pressure and the higher its dynamic pressure. Does this make any difference anyways, if the dynamic ...
3answers
38 views

### Two qubits system in polar co-ordinates

I know that I can write a single qubit state in terms of polar co-ordinates $(r,\theta,\phi)$ on a Bloch sphere. \rho = \begin{pmatrix} \frac{1+r \cos\theta}{2} &\frac{r \exp(-i\...
3answers
485 views

### Is there any effect on mechanical waves by electromagnetic waves (and vise versa)?

Do electromagnetic waves like light and gravitational waves (due to moon for instance) affect on mechanical waves like sound? Can sound change the path of light?
0answers
19 views

### Wave equation for odd spacetimes and source terms

It seems to be quite common practice, when solving the wave equation in spacetimes with odd topologies or horizons, to decompose the solution into a sum of the various origins (or destinations) of the ...
1answer
53 views

### Metric with Harmonic Coefficient and Stress-Energy Tensor in General Relativity

I have two question: Is there any possible implies or interest to use in general relativity a metric whose coefficients are harmonic functions? What is the meaning (physical) if the stress-energy ...
1answer
34 views

### Vibrations of a string [on hold]

A string with length $L$ is stretched between two fixed points. The string can't vibrate with which wavelength? Four options are given, namely $L$, $L/2$ , $2L$ and $4L$. I know that the ...
0answers
15 views

### Are electrons packets of energies made up of strings? [on hold]

I always wondered that if electron was a packet of energy it would hold true for most of the experiments and we won't need to deal with wave particle duality anymore,but then matter came in.what if ...
1answer
28 views

### Tention in a string with pulley and two objects at opposite ends

Tension is confusing me. According to my understanding of tension the tension in a string is uniform but while going through the solution of a problem I read that tge tension on the left part of the ...
0answers
28 views

### Imagine I'm on a spacecraft that was accelerated to 1.0$c$ could I only move backwards? [duplicate]

Imagine I'm in a sapcecraft1 that is moving with 1.0$c$ or at least is so close to that speed that a few miles per hour would just be left to reach $c$. So when I'm traveling now in the direction ...
0answers
34 views

### Building a solid foundation for Quantum Information [on hold]

For the student with a keen interest in Quantum Information, what would be a sound course/set of prerequisites(possibly along with a few good resources) in Math, Physics, Computer Science, Electronics ...

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