Finding the inverse of a matrix using transformations?]]>

Im guessing it's due to increased momentum but the rope...

A climber on a rope]]>

I am currently an Undergrad physics student from Brazil studying in the US, once I am done I will pursue my PhD in some other university, since my current one, unfortunally, does not have a Physics Grad program.

My dream...

Physics Graduate School in UK/Germany/Europe]]>

If higher temperature is correlated with shorter emitting wavelengths, how come there are incandescent light bulbs that emit yellowish light but are hotter than incandescent...

Emission spectra of different materials]]>

The Mobile Information Divide]]>

View attachment 205960

cos 2theta = costheta^2 - sintheta^2

cos2theta = 1

2theta = 0, 2phi

but i get wrong answer.. how is it?]]>

Boundary conditions in dielectric problems]]>

Two objects of equal masses A and B are connected to a system of pulleys as shown in the figure uploaded. The pulleys are assumed to be smooth. Calculate the acceleration of A.

F=ma

Help with this pulley question please]]>

Water temperature.

If I have a 100L bathtub. How much boiling water (100C) will I need to get the bath to a nice 38-40C, if the cold water I'm pouring in is 5C.

The practicality of this question is because I built a bath tub outside, but my hot water system...

The perfect bath?]]>

1. V for C1

2. Let's Say "C" is Resistor then C1 = R1 etc. how to get Eq Resistance for this Circuit ?

Faraday's Law, Kirchoff Law

Complex Capacitor Circuit (for me)]]>

I dont understand very much, if you know pleas help me. Thanks!!!]]>

How much energy is required to accelerate a charge?]]>

Rotating disc in a rotating magnetic field]]>

here is my problem :

View attachment 206062

like usual, the problem is related with RLC circuits and transients

View attachment 206063

from here,...

problem with series RLC circuit and dependent source]]>

http://pro.moneyweekresearch.com/FTI-launch-29AIMAD/PFTIS7A1/Full?h=true]]>

Clarification on the motor rotor position]]>

Books on mathematical logic, foundations, and philosophy]]>

Suppose we have vectors coming in order as A, B and then C (but A must be deleted before C comes in). Then how to get the dot product between A and C? It is allowed to store some calculations of A before deleting elements of A, for example, we could store norm of A, dot(A, B) and etc....

Dot Product of Streaming vectors]]>

Question: An ant starts at one vertex of a solid cube with side of unity length. Calculate

the distance of the shortest route the ant can take to the furthest vertex

from the starting point.

Now, in the answer, the cuboid is...

What's the shortest length here?]]>

Im familiar with the concept that electric field has associated energy with it

Now if in space an electron apppeared at some instant t=0 then electric field will not be established instantaneously but will propagate at speed of light through space

As electric field is bieng...

Energy,charge and electric field]]>

I was looking for references...

p-p -> d]]>

One technique of (purportedly) solving a controversial probability problem is to propose an "equivalent" problem whose solution is not controversial. (e.g. The Sleeping Beauty...

Definition of "equivalent" probability problems?]]>

View attachment 206076

Let ##k^u## denote the KVF.

We have that along a geodesic ##K=k^uV_u## is constant , where ##V^u ## is the tangent vector to some...

General Relativity geodesics, killing vector, conserved quantities]]>

question attached

View attachment 206048

Attempt :

Check if ##V^{\alpha}\nabla_{\alpha}V^u=0##

Since Minkowski space, connection tensors/christoffel...

General relativity, geodesic question]]>

To show that ##K=V^uK_u## is conserved along an affinely parameterised geodesic with ##V^u## the tangent vector to some affinely parameterised geodesic and ##K_u## a killing vector field satisfying ##\nabla_a K_b+\nabla_b...

General relativity, geodesic, KVF, chain rule covariant derivatives]]>

Automotive Engineering advice]]>

Say I have a well insulated rigid container containing some mass

Thermodynamics Entropy of an Isometric Process]]>

Metric transformation under coordinate transformation]]>

From Wikipedia -”Mach’s...

Inertia and Mach's Principle]]>

Suppose there is an observer S on a planet and an observer S'...

Special relativity implies the space cannot be "closed" ?]]>

then

each of Alice and Bob would have obtained a definite outcome.

_____

Consider the following two conditions:

Seeing the essence of Bell]]>

Hi, I am doing physics lab on finding coefficient viscosity of fluids and how it changes by temperature by dropping a marble into fluids, finding terminal velocity, then using stoke's law to find viscosity. (using density of...

Viscosity and temperature, density is changing...]]>

In the figure provided, two suitcases are on a 6.36 m high ramp to passengers waiting in a baggage terminal. The top suitcase is released from rest, and it slides down the ramp and hits the second suitcase. If the suitcase at...

Inelastic collision: block moving down a frictionless ramp]]>

If I choose to view the

1) The

State Separability & CFD]]>

In thinking about vision, especially color vision, I understand that color as such is not a real property of the external world. Nor for that matter...

Why "light"?]]>

And is possible to get a list of galaxies that display these attributes? I would like to use the data for a project.

Thanks guys.]]>

One complete oscillation of a spring: The spring starts off stationary, meaning it has no...

Spring energy conversions - help please]]>

I've been digging around for high resolution photos of distant stars now for awhile. The search has been pretty difficult.

If what I've been reading is correct then there appears to be a limit to viewing small objects like stars, if this is true can someone help me understand the reason...

Where can I find high resolution photos of distant stars?]]>

According to the book "Renewable Energy on Power Systems" by Freris & Infield, the voltage rise due to injection of power in pcc can be estimated from the Thevenin equivalent representing the network "upstream" pcc (Figure 1). The Thevenin voltage can be taken as the nominal voltage in the...

DG connection: Model for Steady State Voltage rise in Point of Common Coupling (PCC)]]>

I want to integrate only x and maintain the argument y present in the rest of calculation, like a global variable. In fortran 77 I would use common.

Question 2:

How to integrate using arguments in the...

How to integrate when one of the limits is a variable?]]>

I am designing a rather simple excel program for work that deals with vibrations in robots. Imagine a robot that is made up of linear axes that can move in x,y,z sort of like a 3D printer, take a look at this picture:

https://pasteboard.co/8hvV5vf.png...

Vibrations in cantilever beams]]>

Difference between field and wave equation]]>

Planning to buy a first telescope?]]>

b = 2*(-zs + Ax*(Bx-xs) + Ay*(By-ys))

c = zs^2 + (Bx-xs)^2 + (By - ys)^2 - R^2

This is part of a code in Matlab, and works fine. It is derived from substituting (x=Ax*z+Bx, y=Ay*z+By) into:...

Intersection between line and cylinder]]>

Do differing frequency light beams asymmetric curve?]]>

Integration in General]]>

Is there significant chance,...

Earth's climate in 100-200 years]]>

Because of the way that series-wound generators are constructed, they possess poor voltage regulation capabilities. For example, as the load voltage increases, the current through the field coils also increases. This induces a greater emf that, in turn, increases the...

In a basic series-wound generator, what is "load voltage"]]>

Amplituhedron and E8]]>

Find the transition matrix ##P## of a transformation defined as

##T:ℝ_2→ℝ_3##

##T:\begin{bmatrix}a\\b\end{bmatrix} = \begin{bmatrix}a+2b\\-a\\b\end{bmatrix}##

For basis...

Transition Matrix of T]]>

Playing trombone to 'wildlife':

]]>

Hey all, I'm Brandon]]>

Rotation of a small drum of mass moment of inertia 0.44kg.m^2 and with frictional resistance torque 0.3 N.m is initiated by a string wound around its 20 mm diameter shaft and attached to a stretched spring, as shown in the...

Rotation of a drum attached to a spring]]>

I don't know if I'm on the right forum to ask this, but maybe somebody knows anything about brightness temperatures measured by remote sensing devices.

In a paper that I read "Atmospheric corrections for retrieving ground brightness temperature at commonly-used passive microwave...

Brightness temperature in remote sensing]]>

--

lightarrow]]>

When Einstein first proposed GR.. did he mean it to have fixed curved background or dynamical?

2. As I understand it. At present. We treat GR as fixed curved background.. so that when we do QFT in curved spacetime, we fix the...

no prior geometry and QG]]>

neutron velocity, energy change time/distance]]>

Help designing self-taught astrophysics curriculum]]>

cheers,]]>

Confused about future]]>

Use definition (1) to determine if the functions ##y_1## and ##y_2## are linearly dependent on the interval (0,1).

##y_1(t)=cos(t)sin(t)##

##y_2(t)=sin(t)##

(1) A pair of functions is said to be...

Linear Independence of Two Functions]]>

Quantum bits information lost in black holes]]>

I am currently focused on Ch. 24: Abstract Groups ... ...

I need some help in understanding some claims in Chapter 24 by Anderson and Feil ... ...

Anderson and Feil claim that ##\text{Aut}( \mathbb{R} )## is the trivial...

Groups of Automporphisms - remarks by Anderson and Feil ...]]>

My wife just drew this

View attachment 93241]]>

Objects outside of the event horizon feel the pull of the black hole - so the closer the object is to the event horizon but still outside of it the more pull the object feels to be sucked into the event horizon? Is that the correct view?

As far...

Black hole radiation]]>

Particle accelerator question -- when the protons "crash" particles are created]]>

A fly in an elevator]]>

Which software support step-by-step solution display like...

Personal/home editions]]>

1) 30x30x8 (cm)

2) 40x60x8 (cm)

literally breaking it in half with a fulcrum underneath and two forces acting on the top

i've posted a number...

breaking a granite surface plate...]]>

In Mathematica and given the code below, I am trying to the real part of ##\sigma##, ##Re(\sigma)##, in stead of simply ##\sigma##. Any help would be awesome! Here's what I have:

Code ( (Unknown Language)):

n = 3;

ContourPlot[(\[Sigma]^2 -

2 (n - 1) (2 n + 1) \[Epsilon] \[Sigma] + (n - 1) n...

Pardon my lack of knowledge, but I am aware that low caliber bullets can penetrate water past 3ft (Thank you Mythbusters). However, the tests they completed were all based around a pool...

Water speed and bullet penetration]]>

source...

weak gravity conjecture and strings vs loops]]>

Three objects of equal mass, A, B and C, are released from rest at the same instant from the same height on identical ramps. Objects A and B are both blocks, and they slide down their respective ramps without rotating. Object...

Dynamics of rigid bodies]]>

Strength between magnets]]>

Three identical rectangular blocks are at rest on a level, frictionless surface. Forces of equal magnitude that act in the same direction are exerted on each of the three blocks. Each force is exerted at a different point on the...

Acceleration of center of mass]]>

My professor said that since gravity pushes down any object on earth, the objects themselves push up against earth. Intuitively this is difficult too grasp, can anyone give an example or anything to help me out. Thank you]]>

Also does anybody have any opinions on the book "From...

Additional QFT textbooks]]>

1. Air resistance force

[tex]F = C_d \frac{\rho v^2}{2}S[/tex]

2....

Cannonball - time required to stop its horizontal motion]]>

View attachment 205834

View attachment 205835

Just help me with 18 b.

V

Impedances in a 5 element circuit]]>

The regular physics teacher taught this course a few years ago and has some powerpoints, lessons, documents, etc. but they are...

Help -- Summer school physics class]]>

- deflection of light by the sun

- precession of perihelia of planets

Also, as our solar system is not isotropic nor static, it seems that by using the Schwarzschild metric we would get only an approximation on...

Why Schwarzschild metric?]]>

- Sending end power = 3.75MW

- RL=5.18 ohms

- XL=130 ohms

- VS (Generator bus)=161kV

- VR (Infinite bus)=161kV

- Sending end voltage angle (delta) = 0.01877 (Angle which allows 3.75MW to be transferred)...

Calculating the reactive power of a transmission line]]>

I am trying to fill in the steps between equations in the derivation of the coordinate representation of the Darwin term of the Dirac Hamiltonian in the Hydrogen Fine Structure section in Shankar's Principles of Quantum...

Commutator in the Darwin Term]]>

i got little confused after this conversation