0
votes
0answers
2 views

Why does surface tension of water-ethanol binary mixture decrease with increasing concentration of ethanol?

I was thinking that it must be due to weaker hydrogen bonding in ethanol than in water. But then I learnt that Raman Spectroscopy and viscosity measurements suggest that upto a certain ethanol ...
0
votes
0answers
9 views

time as consequence of hadronics

it has occurred to me that time is solely consequence of non-electric fields, with latest work being reading about «anapole» cite: Simple theory may explain dark matter due to ...
1
vote
1answer
8 views

Earth density distribution from shooting neutrinos?

I am interested in possibility of inferring Earth interior structure from gravitational data. As classical calculus problem shows, it is impossible to understand non-uniform density distribution ...
-1
votes
2answers
23 views

How to determine the angular velocity of a particle with mass $m$ and charge $q$ in a constant B field?

$\textbf{PROBLEM:}$ A particle with mass $m$ and charge $q$ moves in a constant magnetic field $B$. Show that, if the initial velocity is perpendicular to $B$, the path is circular and the angular ...
0
votes
1answer
17 views

Is the electrostatic field really static? Does thermal vibrations not affect it?

We know that if a conductor has any net charge, the charges reside on the surface. The electric field immediately outside the surface is perpendicular to the surface. But the charged particles, say ...
0
votes
0answers
7 views

How do you calculate the electric tension between two charged entities?

If: 1) you know the coordinates and individual charge(in coulombs) of each object and 2) voltage is the difference in electric potential energy between two nodes How do you calculate the voltage in ...
1
vote
1answer
22 views

Is entropy a meaningful concept on a quantum level?

My naive assumptions, as I really am at a pretty basic stage in QM, are as follows: Classically, entropy gives us a practical measure of the direction of time, as opposed to our physical laws which, ...
0
votes
1answer
7 views

longitudinal magnification confusion in concave mirror

If you move a rod lying on the principal axis of any concave mirror, when the near end of the rod is at a distance equal to half it's own length from the mirror, then the instantaneous velocity of ...
0
votes
0answers
40 views

Any other mathematical fields in physics than $\mathbb{R}$ or $\mathbb{C}$?

In physics, we usually use the real number field $\mathbb{R}$ or the complex number field $\mathbb{C}$. Does any other field find use in physics too?
0
votes
0answers
7 views

BiCopter simulation problem [migrated]

I derived bicopter dynamical model with two servos and two BLDC motors. And now am trying to simulate it using Matlab. As base for simulation I used this paper and this code: ...
0
votes
0answers
11 views

Centripetal Force Doubt

I have'nt understood the solution that has been provided: Question: Solution : I did'nt understand the part where they stated that for the water to not fall out of the bucket, N>= 0 I'm a high ...
0
votes
0answers
14 views

The induced electric field of an infinite current carrying wire

I am given, without motivation, that the induced electric field from an infinite, straight, current carrying wire is parallel to the wire itself. $$ \vec{I} \times \vec{E}_{\text{induced}} = ...
0
votes
1answer
4 views

Is the retentivity of soft iron more than that of steel?

Permanent magnets must have high retentivity and high coercivity and steel is used as one. So it should have higher retentivity.
0
votes
1answer
21 views

Help with proving a relation

I am trying to see if the following relation, \begin{equation} \frac 12 g_{ij}\frac{d^2\eta}{du^2}+\frac 12 g_{ij}\frac{d\eta }{du}+\frac 12 \frac{\partial g_{ij}}{\partial x^j}\frac ...
-2
votes
0answers
12 views

Magnitude of force of air resistance

A 68 lbf prefabricated slab is hoisted by a rope. The rope pulls with a force of 751.9 N at an angle of 6.6° to the left of vertically upward. The only other force acting on the slab is the force of ...
0
votes
0answers
9 views

Wimhurst machine - How does it work?

Look at this VIDEO to see what is supposedly happening: A Wimhurst machine is a seemingly simple device consisting of two plastic wheels with embedded metal plates on the rim. The wheels spin in ...
0
votes
2answers
34 views

Is gravity actually missing or lower in certain spots on Earth?

I have heard and read about "missing gravity" in some regions of Earth. What I seemed to gather from this info is that if I go to a certain spot and jump, I can jump higher; or I could maybe lift more ...
0
votes
0answers
10 views

Can any one explain how to obtain the frequency distribution versus density of state, from dispersion relation?

How to compute phonon frequency spectrum or ohinon distribution of an element.
0
votes
0answers
6 views

Baryonic current nonconservation due to anomalies

Let's have baryonic current: $$ j^{\mu}_{B} = \frac{1}{3}(\bar{u}\gamma^{\mu}u + \bar{d}\gamma^{\mu}d + h.c.) $$ It can be shown that due to anomaly its conservation is forbidden: $$ \tag 1 ...
1
vote
1answer
23 views

Is the MaxEnt “interpretation” of statistical mechanics the current mainstream approach?

I've only recently started studying statistical mechanics and I'm quite confused with the MaxEnt and anti-MaxEnt ideas. I'm looking for a concise answer, if it is possible, not really a description or ...
2
votes
0answers
27 views

Tensors, indices and matrix notation - is there a common convention?

For a tensor named T with two indices, there are four possibilities: $T_{ij}$ , $T_i^{\ j}$, $T^i{\ _j}$ and $T^{ij}$. Is there a common convention as to how these tensors would be represented as ...
0
votes
0answers
16 views

If a probe barely escapes a black hole doesn't its clock slow down?

That is, wouldn't a probe traveling just far enough away from a black hole to not fall in show less time on it's clock compared to the spacecraft when it returned (gravity time dilation)? If so, ...
0
votes
0answers
17 views

How is ampere defined for alternating current?

Both alternating current and direct current are measured in ampere. But how is ampere defined for alternating current? It cannot be defined from two mutual attraction of two parallel wires carrying ac ...
1
vote
0answers
17 views

can light bounce off another light?

If light is a wave and a particle (wave particle duality), is it possible for light to bounce off another light since light bounces of another matter(particle)?
0
votes
0answers
7 views

Regarding IMU derivation of position/orientation

If you are familiar with IMUs (Inertial Measurement Unit) , you know that before the double integration to arrive at estimating the position, one has to subtract the gravity from the measured ...
0
votes
1answer
11 views

How do you calculate minimum speed for a mass to move vertically in a circle

For part c) would you subtract the top and bottom tensions to find the minimum velocity. The answer should =2.7 m/s for part c).
-3
votes
3answers
70 views

Is there free will? [on hold]

From what I've understood about the answer to this question quantum physics doesn't contradict determinism, but instead it simply isn't achievable only because of our universe's nature: we are unable ...
-1
votes
1answer
31 views

Differentiation of a vector with respect to a vector

Does differentiation of a vector with respect to a vector make any sense? Even if it makes sense, how does it make any physical meaning? I mean what is the physical interpretation?
0
votes
1answer
76 views

Certain doubts regarding the facts shown in 'Interstellar'

In the movie, or rather a scientific fiction, Interstellar, we saw in the last part, that the actor falls into the black hole, travels in time, which is a dimension inside the black hole, and then, ...
0
votes
1answer
17 views

Light Spectrum - Sum of Waves or Collection of Waves

I'm wondering about the spectrum of light that is often shown pictorially as a distribution of power, say, from sunlight. My question is: does this indicate that each wave of light contains all of ...
-1
votes
2answers
32 views

Block over a Block Problem.

This a block placed on block problem. In this problem, A block with mass 40 kg in placed on a block of 60kg which lies on a frictionless surface. The coefficient of friction between 40kg mass and 60kg ...
0
votes
0answers
21 views

Does a switched on power socket consume electricity? [migrated]

Lets say I have a TV and a power socket but the TV switch is off however the socket switch is switched on, so will it consume electricity?
1
vote
1answer
24 views

Why does in the definition of 'optical path', only spatial phase change is taken into consideration & not that of time?

In Concepts of Physics by H.C.Verma, I got the definition of optical path. However, one thing that I couldn't understand is why only the spatial phase change is considered in its definition. As he ...
-1
votes
3answers
37 views

How to calculate the linear speed without angular velocity

How would you calculate question (f) the linear velocity, without a angular velocity. The radius of the circle is 0.6m. The answer (linear velocity) should = 1.84 m/s
3
votes
3answers
66 views

Is work done by a pseudo force?

If a body is viewed from the frame of another body which is itself accelerating will work be done by the pseudo force acting on first body in the frame of second body ( provided the first body is ...
0
votes
1answer
29 views

Are the particle-antiparticle pairs produced in vacuum virtual particles, and can they interact with normal particles?

If it is true that due to energy fluctuations of a vacuum being able to produce a particle-antiparticle pair that shortly annihilate with each other and disappear again, is the following circumstance ...
0
votes
0answers
13 views

Laser Energy Level Transitions

I am new to Laser Physics. While looking at the Energy Levels diagram for the Laser Transition of ND:YAG laser, I see energy levels labeled like 4F(3/2), 4I(15/2),.. I did not come across such energy ...
3
votes
0answers
33 views

Why is a vertex a derivative of the propagator?

Where can I find the answer to my question: if the momentum is small, the vertex is the derivative with respect to the mass of a propagator times a factor (-m/v) like in the picture:
-3
votes
0answers
26 views

Radio active isotopes [on hold]

Radio active 54fe at mass 15g is given activity of 3700000 meters per second and then inserted into an engine.After 100days of continuous use,the crank case oil was found to have a total of activity ...
0
votes
1answer
23 views

Formula connecting Force and Power

Is there such formula? There probably is of course, but i would like a very concise description of how to derive it, in order to better understand myself. Thank you in advance.
8
votes
1answer
291 views

Tesla coil arc in air - where is it going?

here is a picture of a Tesla coil with a discharge that seemingly terminates in the air. What completes the circuit at the end of the streamers?
2
votes
1answer
25 views

Diffraction experiment at home

I have bought a laser tachometer, can you tell me if it is possible to make a diffraction experiment at home? How can one make a slit of 630 nm? As a side question: light bouncing on reflective tape ...
0
votes
1answer
22 views

How to reduce cooling time of hot aluminum casting / block?

I am doing project on "reduction of cooling time of hot Aluminium casting/block". Aluminum casting / block temperature is 250degree C (532 K), size diameter 600mm x 150mm and weight 25kg. In order ...
0
votes
1answer
21 views

entropy balance equation in thermodynamics [on hold]

can any body help me to prove the following entropy balance equation. \begin{equation} T \frac{ds}{dt}=- div \mathbf{q} \end{equation} where $T$ is absolute temperature and $s$ is entropy $\mathbf{q}$ ...
1
vote
0answers
20 views

water permittivity

I made a water sondе from one sided FR4. The plates are parallel, copper sides are counterclaims. The plates are $5\times 50$mm, spaced at $7.5$mm. The expected value of capacitance is ...
0
votes
1answer
26 views

Fourier expansion and transform - what about the phase of the waves that i am adding?

Say we have a wave on the surface of the water and we want to describe it as a sum of other waves. So we use Fourier expansion to add waves of different wavelengths. For simplicity, say we have to ...
0
votes
1answer
52 views

Black Holes and Einstein Field Equations

I recently watched a video where Michio Kaku argues that there must be something fundamentally wrong with the theory of General Relativity because it gives time t=0 as a solution at the centre of a ...
-1
votes
0answers
24 views

An experiment at home: cinematic 3d [on hold]

I would like to know if I'm right when I experiment this at home: The support (grey color) turns. The purple disk don't turn around itself at start but it can. The point A is fixed on the purple ...
0
votes
2answers
42 views

how current flows in a parallel circuit as the potential difference is same?

Since we know current can not flow in a wire if there is no potential difference in its two terminals. How current flows in a parallel combination where each load has equal potential difference in ...
0
votes
0answers
20 views

What came before the Big Bang? [duplicate]

Is it an inflating bubble in a space time foam? Some concluded that "whereof one cannot speak, thereof one must be silent"

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