which formula is correct ? the formula in the first ? or in the second ? one is using the mean velocity , while the another one is using velocity difference between vena contarcta and velocity at exit ....

minor loss in pipe]]>

I am trying to calculate the equation of motion of a charged particle in the field of a monopole.

The magnetic field of a monopole of strength g is given by:

[tex] \textbf{B} = g \frac{\textbf{r}}{r^3} [/tex]

And the Lagrangian by:

[tex] \mathcal{L} = \frac{m\dot{\textbf{r}}^2}{2}...

Lagrangian of a monopole (Einstein notation is used)]]>

A finite arithmetic progression is given such that ##S_n>0## and ##d>0##. If the first member of the progression remains the same but ##d## increases by 2, then ##S_n## increases 3 times. If the first member of the progression...

Arithmetic progression]]>

Need to find the pressure difference between the two water pipes. Specific gravity of water = 1000 kg/m^3, specific gravity of oil = 800 kg/m^3

pressure = height * specific gravity * gravitational...

Calculate the pressure difference between two points]]>

I once read that Carl Sagan proposed the idea by spreading bacterias in...

Venus, terraforming]]>

In high school, we usually take examples where the object is placed in an incline and the Normal force is equal to mg cos theta where theta is the angle of the incline. It should equal to that...

Normal forces question]]>

The time t' starts when the hammer is expected to drop...

Like Schroedinger's Cat]]>

Newtonian vs Relativistic Mechanics]]>

In my Nuclear Power assignment I decided to analyse this graph:

I mention that

"The difference in atomic mass and binding energy per nucleon for deuterium and helium (fusion elements) is ≈3u and 5.96 MeV...

Binding Energy per Nucleon trend for fusion vs fission]]>

1. Is $$((A\otimes I\otimes I) + (I\otimes A\otimes I) + (I\otimes I\otimes A))\otimes B$$

= $$(A\otimes I\otimes I)\otimes B + (I\otimes A\otimes I)\otimes B + (I\otimes I\otimes A)\otimes B$$?

2. Is $$(A\otimes...

Simple question about tensor product properties]]>

If W is represented as the point shown in blue which of the other points satisfy z=Sqrt[w]?

View attachment 100202

View attachment 100203

Complex Plane - Graphing Powers]]>

The interaction Hamiltonian is:

$$\sigma_1^x\otimes B_1 + \sigma_2^x\otimes B_2$$ where $$B_i$$ is a 2 by 2 matrix.

I try to interpret and understand this, is it the same as:

$$(\sigma_1^x\otimes B_1)\otimes I_2 +...

Interaction Hamiltonian coupling question]]>

This week's contest will run for 2 weeks, and the winner will get a prize!! The prize will be the book "Black Hole Blues and Other Songs from Outer Space" by Jenna Levin....

PF Photo Contest - Gravity (4/30-5/13)]]>

the author stated that Q1= Q2 + Q3 , that's means the water flowing from reservoir A to B and C ....

why cant Q1 + Q2 = Q3 ??? which means water flow from...

Flow in branch pipe]]>

Look for the auto parts importers.]]>

calculate R

C = 40 μF

R

L = 9mH

image : http://postimg.org/image/kampvczv5/

ω = 1/sqroot(L*C)

Resonance in parallel RL-RC circuit]]>

A stationary wave travels along a stretched string. Part of this wave at a particular

instant is shown....

Graph of stationary wave after moving for half period]]>

How to unscrew a nut from a generator]]>

On the picture, ##ABCD## is a parallelogram, ##(EF) // (AB) ##, and ##(GH) // (BC)##.

The problem is : show that lines ##(EB)##, ##(HD)##, and ##(IC)## either all meet in ##M##, or are parallel.

geometry question -- several lines through parallelograms]]>

what force keeps a radially accelerating object in the air?]]>

I'm sorry that I'm posting something that might be obvious, but I'm still struggling to capture all the concepts behind the fundamental physics of this model.

Let's say, I have a 2D sheet of graphene, on which, theres a physisorbed layer of molecular dipoles (vdW bonding, no...

Effect of SAM physisorbed on graphene - some questions]]>

i)...

Thermal expansion]]>

I've read that it's actually the electromagnetic force, but atoms are electrically neutral and there is no ostensible repulsive force between electrons and the nucleus, so I have some doubts.

Has...

Quantum Model of Contact Forces]]>

Software - Suspension Analyzer by Performance Trends

In order to understand the complexity of a Formula Cars suspension, a basic knowledge of the stock car suspension should first be mastered. When...

Race car suspension Class]]>

I want to know why the answer is C not B. Thanks.

F=kx

I have recently performed an experiment where the voltage drop and current through a diode were measured. I am wondering why the voltage drop across the diode changes. Theoretically, the voltage drop should stay the same as...

Voltage Drop Across a diode]]>

Seem to me that lots of theories was built on other's ones and...

H boson is 125 GeV, super symmetry, multiverse not possible?]]>

GWs energy and aLIGO detection]]>

Captain America Civil War Physics Question (spoilers)]]>

"Spacetime" (what is "it"?)]]>

Here is the last page of part 4. https://www.physicsforums.com/threads/random-thoughts-part-4.786642/page-201]]>

Capstan law is T2=T1e^μθ.

I have problem identifying T1 and T2 in various situations:

1) when the capstan is not rotating

2) when the capstan is rotating

how can I identify which side is T1 and which T2?

thanks!]]>

And the photons of light...

Few questions on light interacting with atoms]]>

Parametrisation of timelike curves using proper time]]>

I am trying to understand what ##[g_E]## is here? Since in this set up we are summing over...

Superficial degree of divergence for scalar theories]]>