0
votes
0answers
25 views

Baseball innovation [on hold]

I am working on technology for pitchers that will go inside of a baseball and give feedback on the velocity of the baseball, the spin of the ball, the direction of the spin, and the acceleration. I am ...
0
votes
0answers
20 views

A free jet of liquid (incompressible) strikes a wedge as shown in figure below [on hold]

A free jet of liquid (incompressible) strikes a wedge as shown in figure below.
-1
votes
0answers
14 views

For a velocity field u(x, t) r r in a fluid of density (x,t) r r , show that [on hold]

For a velocity field u(x, t) r r in a fluid of density (x,t) r r , show that
-1
votes
0answers
10 views

Use conservation of mass and Newton’s second law to obtain pressure coefficient and show that p2 > p1 [on hold]

Use conservation of mass and Newton’s second law to obtain pressure coefficient and show that p2 > p1
0
votes
0answers
24 views

Equivalent Force from Pressure [on hold]

I am trying to find the force at a certain point of a plate due to some pressure. I have a picture below (terribly drawn, sorry) but basically I have two plates with hinges on one side and the plates ...
2
votes
0answers
34 views

Ricci tensor of direct product of manifolds

Imagine I have a (Lorentzian) manifold with a metric $\left[ {\begin{array}{cc} g_{\mu\nu} &0\\ 0&g_{mn}\\ \end{array} } \right]$ Will the Ricci tensor be also block diagonal ...
3
votes
1answer
25 views

Correlation between large-scale galaxy structure and CMB fluctuations?

During a relatively non-technical astronomy seminar the other day, the speaker displayed the famous WMAP full-sky image as an aid to describing what the CMB is, the scale of its fluctuations, etc. ...
0
votes
1answer
24 views

What is the eastward deflection due to Coriolis force [on hold]

Suppose, an air parcel is at the equator, and it has a northward velocity of 10 m/s. Due to Coriolis force, what is the eastward deflection of the parcel when it reaches 30N. Please show full ...
0
votes
1answer
32 views

Projectile Motion on an inclined plane [on hold]

There are two parallel planes, each inclined to the horizontal at an angle $\alpha$. A particle is projected from a point, midway between the two planes, such that it grazes one of the planes and ...
1
vote
3answers
49 views

Do atoms of a surface excite to reflect the light?

How do surfaces reflect certain colours and absorb the others?
0
votes
1answer
43 views

Centrifugal force for non uniform circular motion [on hold]

If a body is under non-uniform circular motion, will it experience or will there be any impact of centrifugal force on the body upon eliminating the centripetal force? update-sorry.the title of ...
0
votes
0answers
8 views

2 calculations on absorbed and exposure dose [on hold]

1-A beam of 4.5 Mev neutrons is directed at 0.03 Kg tissue sample. Each Second 1.5×10^6 neutrons strike the sample. If the relative biological effectiveness of these neutrons is 7.0 . WHAT ...
0
votes
1answer
48 views

Send a signal from Earth to a planet billion light years away instantly [duplicate]

If light was infinitely fast, we could just send a light signal from Earth to the planet. But I was wondering, if we made a perfectly non-elastic rope as long as the distance between earth and the ...
2
votes
1answer
81 views

$SU(2)$ gauge symmetry

Take the Lagrangian with one fermion: $$ \mathcal{L} = -\frac{1}{4}F^{\mu\nu}_aF^a_{\mu\nu} + \bar{\psi}(i\gamma^\mu D_\mu - m)\psi$$ where the gauge covariant derivative $D_\mu = ...
1
vote
1answer
20 views

Why do tropical cyclones not tear themselves apart?

A tropical cyclone is the generic term for a hurricane, typhoon, or tropical storm. Tropical cyclones derive their energy from evaporation of water at the ocean surface which ultimately recondenses ...
1
vote
0answers
32 views

2 Nucleon Potential

I am looking at a 2 Nucleon potential of the form $$V(r)=V_0(r)[a+bI_1\cdot I_2]$$ Where a and b are constants. $I_1,I_2$ are isospins. $V_0(r)$ is of the square well form. My goal is to find an ...
2
votes
1answer
28 views

Curvilinear coordinate system around body of revolution

In Boundary-Layer Theory by Schlichting he gives the boundary-layer equations for a body of revolution according to the paper by Boltze$^1$. Unfortunately, this paper is in German. He apparently uses ...
0
votes
4answers
65 views

What happens in a circuit, when the wire and the battery are superconducting. And shorted

When a wire with no resistance is connected to the terminals of an ideal battery, will a current exist in the circuit? If a capacitor is added to the circuit, will it be charged by the battery or will ...
0
votes
2answers
37 views

Joining 2 capacitors in a circuit [on hold]

Consider 2 capacitors having capacitance $C_1$ and $C_2$ charged to potential $V_1$ and $V_2 (V_1>V_2)$. If a circuit was made in which just the 2 capacitors were connected together, would it ...
3
votes
1answer
55 views

What is the difference between mechanical and thermodynamic pressure?

To start with I know thermodynamics deals with processes at equilibrium. Hence the thermodynamic pressure should most likely be the pressure of a fluid at equilibrium. I'm not sure if a fluid flow ...
3
votes
1answer
78 views

Does water turn solid under deep ocean because of high pressure?

I know that we can make water solid with high pressure, so I think water will be solid in the deep ocean? If that is true, the depth of the ocean would be limited because water will become ice? ...
11
votes
2answers
379 views

Why uncertainty principle is not like this?

In Griffiths' QM, he uses two inequalities (here numbered as $(1)$ and $(2)$) to prove the following general uncertainty principle: $$\sigma_A^2 \sigma_B^2\geq\left(\frac{1}{2i}\langle [\hat A ,\hat ...
1
vote
0answers
10 views

Cubic Gaussian Surface For Evaluating Electric Flux

i'm working through some problem sets about Gauss' law and all the examples I have come across so far require the use of a spherical gaussian surface for a point charge, so that it is possible to say ...
4
votes
0answers
88 views

Degenerate perturbation theory applied to topological degeneracy?

Consider a quantum system described by a gapped Hamiltonian $H_0$ with degenerate ground states (GS), adding a perturbation term $V$ to $H_0$, then the low-energy physics can be described by an ...
0
votes
1answer
24 views

Calculating the distance between Detector and Double Slit

I have a little problem that is kind of confusing me at the moment. The following task: Light of the wavelength $\lambda = 500nm$ hits a double slit whose distance is $a = 30\mu m$. Each is $a = ...
0
votes
1answer
75 views

Relative motion. Setting course of closest approach (Requested resource recommendation as well)

Let $r_{P/Q}$ be the position vector of $\overrightarrow P$ relative to vector $\overrightarrow Q$ and $v_{P/Q}$ the velocity vector of $\overrightarrow P$ relative to $\overrightarrow Q$. Suppose ...
8
votes
2answers
1k views

Does it make sense to open one window all the way when the other window is much smaller?

I can't wrap my head around this idea because I don't know much about air flows. Say we have this imaginary apartment with two windows, one of which is two times smaller than the other: Will the ...
0
votes
1answer
46 views

Breakout - physics when ball hits paddle? [on hold]

I'm making Breakout in Java, I've got the paddle and the ball made. The ball has a X and a Y velocity. I've already inverted the ...
0
votes
2answers
52 views

Find pressure of liquids without making contact with it

Is there any way to find the pressure of a liquid inside a closed container without making contact with it? You can make any assumptions, like transparent container or anything, only rule, the ...
0
votes
2answers
27 views

Non-uniform circular motion, computing the angle

There is an object moving in circle, with this law: $$ \alpha = -k^2 \theta $$ With $ \alpha = \frac{ d \omega }{dt} $, and $ \omega= \frac{d \theta}{dt} $, $\theta$ = angle, $k$ positive ...
2
votes
3answers
60 views

Why can colors be mixed? [duplicate]

We can combine colored light, creating other colors, at least in terms of visual perception. But how it the result physically "a different color" - if it is at all? Or is all this not a physical ...
0
votes
1answer
25 views

What is the correct way to take out equivalent capacitance here?

So here I have a capacitor with two plates , one positively charged and one negatively, as shown in the figure. Now the material between them is $k_1$ for thickness d/2 and $k_2$ for the other d/2. ...
0
votes
1answer
29 views

Finding the odd parity bound state wave function for a particle in one dimension

Let a particle of mass $m$ and energy $E$ be moving on the $x$-axis in a potential $V(x)$ given by $$V(x)=\left\{\begin{matrix} -V_{0}, & -a<x<a\\ 0, & otherwise \end{matrix}\right.$$ ...
1
vote
2answers
33 views

Anchor of a boat

hope you can help I've been teaching my kids about pirates and when we were talking about pirate ships this morning I confused myself greatly. When carrying an anchor a pirate ship (or any vessel ...
0
votes
0answers
19 views

Transformers rate equation

Going back to transformers after some years I realize they hide a possible missconception I'm not sure I really understand. It is not easy to find a full derivation of the well known relation ...
2
votes
0answers
42 views

When can I use semiclassical approximation?

I know that I can use semiclassical approximation for path integral approach (in quantum mechanics) $\int d[q]e^{iA}$ when action $A >>1 $. But how shall I use such condition? For example, ...
1
vote
0answers
47 views

Heisenberg Uncertainity Principle

If any senior member of the group has access to the book, The Physical Principles of Quantum Theory by W. Heisenberg, then please help me in understanding the first section of chapter 2 where he gives ...
2
votes
3answers
172 views

Ordering of differential operators

If we write something like: $\partial_a X_{\mu} \partial^a X^{\mu}$ Does that mean the first derivative is only applied to the first X? ($\partial_a X_{\mu})( \partial^a X^{\mu}$) Or is the ...
0
votes
2answers
30 views

Velocity required for orbit of satellite

I am very confused about orbital velocity for satellite launched from earth. It is states that: $$ v=\sqrt{\frac{GM}{r}} $$ Some says that it is equal to 8000 m/s and some say 3.1 km/s. Please remove ...
0
votes
1answer
54 views

Lorentz transformation of electromagnetic 4-potential

I'm looking for the exact correspondence between Lorentz transfer four vector and the four vector of scalar and vector potential $A^\mu = (\phi(t,\vec{x}),\vec{A}(t,\vec{x}))^{T}$. Does $ct=A(t), ...
4
votes
2answers
71 views

Higgs mechanism and neutral fields

Consider a Lagrangian $L(\phi,A_{\mu})$ with $\phi$ being some scalar field and $A_{\mu}$ some dynamical U(1) gauge field that minimally couples to $\phi$. Under a global U(1) symmetry the field ...
0
votes
1answer
18 views

Calculate the effective linear attenuation coefficient of a megavoltage multi-energetic beam

Are you aware of a method or source for calculating the effective linear attenuation coefficient,$\mu_\text{eff}$, of a megavoltage multi-energetic beam ? For a mono-energetic beam one could use the ...
1
vote
1answer
67 views

Wave Function Integral I need help conceptually and Mathematically

$$\int_{-\infty}^{\infty}\frac{\partial^2\bar{\psi}}{\partial{x^2}}\frac{\partial\psi}{\partial{x}}~dx.$$ I have read that this is equal to Zero. Only problem is that what I am reading about doesn't ...
1
vote
3answers
44 views

Energy expended in moving point charge in E field. Having trouble understanding an excerpt from E&M textbook

To move charge from one point to another in an electric field, the force which we must apply is equal and opposite to the force due to the field. (Quoted from Engineering Electromagnetics by ...
1
vote
1answer
34 views

Temperature in a Voltaic Cell

The potential difference across a voltaic cell varies with temperature. But my question is whether the voltage increases or decreases as temperature rises. According to the Nernst equation, the two ...
3
votes
1answer
51 views

Acceleration of electric charges and radiation

According to classical electromagnetic theory, accelerated charges should emit radiation and lose energy. The reason given in my book why atoms don't emit radiation (say, when the atom moves along a ...
0
votes
2answers
51 views

Interpretation of red shift

We see light as having travelled in a straight line from stars or galaxies light years away from us. However it's path is more likely of multiple curves as a result of gravity along the journey ...
0
votes
0answers
20 views

Is amplitude independent of mass in SHM [on hold]

A block A of mass m is under Simple Harmonic Motion according to x=A $\sin \omega t$. A block B of mass 2m is placed gently on it when A is in the mean position (Assume sufficient friction for no ...
-3
votes
0answers
35 views

Gravity problem [on hold]

If :Two objects of the same mass are situated in diametrically opposite points of Earth’s surface to achieve the time to reach the Moon. These objects belong to the centers of the mentioned celestial ...
0
votes
1answer
18 views

Resonance and a tuning fork

I carried out this experiment in class: I struck a tuning fork with a hammer. The sound lasted for some time. However, when I connected the tuning fork onto a wooden sounding box, the sound lasted ...

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