Change Definition and 1000 Threads

Is there any version of string theory or cosmological inflation that allows the most fundamental laws and constants change between universes? String Theory and Cosmological Inflation are two theories or models that allow multiple universes to exist. Laws and constants of physics could change...

I am working on simulating the movement of small spherical objects under the influence of drag and a number of other forces that, at least for now, don't depend on the object's velocity. Normally I would sum up all these forces, including drag, to ##F_\Sigma## and update the object's speed...

Hi, I understand the underlying concept of changing variables in PDEs (so that we can reduce it to a simpler form), however, I am just not completely clear on the mathematics of it so I have a quick question about it. For example, if we have the transmission line equation \frac{\partial...

Reading old text about the limit of large N_c, there are some remarks telling that for finite N we have a colour tube and that it becomes a string in the limit. It sounds as the extra dimension of M-Theory, and I wonder if the math of both calculations are related somehow. Is the transition to...

I have the STRESS , YOUNG S MODULUS ,and the LENGTH . How can you discover the CHANGE IN LENGTH when you don t have the FORCE and AREA unit ?

https://phys.org/news/2020-01-fossil-upend-basic-tenet-evolutionary.html Sandra Catania et al. Evolutionary Persistence of DNA Methylation for Millions of Years after Ancient Loss of a De Novo Methyltransferase, Cell (2020). DOI: 10.1016/j.cell.2019.12.012 Using pathogenic fungus species, the...

If it occurs spontaneously then it must increase entropy but the possible micro states reduce so what else is occurring to increase entropy

Strain and change in length what is the difference ?

As I have shown in the picture even if their is minimal change but shouldn't it increase after a long time as minimal changes will keep accumulating.

I'm currently an AEMT on track to go to Paramedic school. While I still love EMS and intend to stay in the field for as long as it suits me: I still feel myself pulled to studying physics. I've always been drawn to the field since high school. I'm not the best at math but I'm no stranger to...

##dmL_f= Q \; \; ##,##∆T=\frac{T(v_l-v_s)∆P}{L} \; \;##,##\frac{dmL_f}{T_0}= dS_2 \; \;##,##\frac{dmL_f}{T_1}= dS_1 ##

Hi everyone, I tried to solve the last part of the question, I substituted back the expression of x and y into the equation of the ellipse, I got that r=1 or r=-1. But got no idea how to find the boundary for theta, I got a guess that, It should be from zero to pi. But got no reason why to...

1- ##\delta P_V =(\frac{\partial P}{\partial T} )_V \delta T_V## 2-##\delta V =(\frac{\partial V}{\partial T})_P \delta T+(\frac{\partial V}{\partial P})_T \delta P## so ##C_v \delta T=-P\delta V=-P((\frac{\partial V}{\partial T})_P \delta T+(\frac{\partial V}{\partial P})_T \delta P)## I can...

I tried taking log and then diffrentiate the standard equation for time period of a pendulum but i am not getting the correct answer

A steel bar 6.00 m long and with rectangular cross section of 5.00 cm x 2.50 cm supports a mass of 2000 kg. How much is the bar stretched ? (the young s modulus of steel is 20 x 10 n\m squared)

According to the first principle of thermodynamics: ΔU = W + Q Also noting that: W = -P⋅ΔV (Question: This P is the initial pressure or the final?) To find V2: (P1⋅V1) / T1 = (P2⋅V2) / T2 → Therefore, (P⋅V1) / T1 = [(P/5)⋅V2] / T2 → (P⋅V1) / T1 = (P⋅V2) / (5⋅T2) → V2 = (5⋅T2⋅V1) / T1...

This is not to ask for a solution, rather I want comments on the rigor of the step. Thank you for your time! The graph shows a system of two points at ##t## and ##t+dt##, it is a bit exaggerated of course. The upper point is moving strictly in the ##x## direction and has a constant velocity...

Question: This would be the right approach to do this problem? Thanks!

First I have to explain that this is not actually a homework problem. It is a problem I created to use in a sort of game. If I made a mistake, it tends to ball up the game. So I am looking for someone to double check my answer, and to point out any errors in my statement about physics. I prefer...

I got 6.5 MeV but I don't understand how to determine whether the energy is released or absorbed. My guess: the energy is absorbed because mass defect of neon is bigger? Thanks

Summary: When ##V (x) = \frac 1 2 mω^2x^2 + mgx## ##H=\frac p 2m +V(x)## Difficulty understanding how these change on variables came about ##y = x+\frac mg mω^2 = x+\frac g ω^2## Apologies if this is not the appropriate thread. I chose this one because even though it's physics, I'm having...

Just started this topic so I'm not sure if this is the correct way to solve this, any help would be appreciated. mass of object x change in temp x specific heat capacity= heat change in temp= heat/(mass of object x specific heat capacity) Mass= 700kg Specific heat capacity of steel= 0.42kJ/kgC...

In physics we often change a sum to an integral.But I am not clear when can we change a sum to an integral?When a term of sum is comparable to the sum,can we change the sum to integral?

Given the example g = \frac{GM}{R^{2}}, we may compute the change in field strength if the mass is changed by a small amount dM to be$$dg = \frac{G dM}{R^{2}}$$and also if R is changed by dR,$$dg = \frac{-2 GM dR}{R^{3}}$$If, however, both the mass and radius are changed by a small amount at the...

Summary: What if the Earth rotated about its axis in a N-S direction instead of doing so in an E-W direction. Hi, Just curious: What would be the effects/consequences if the Earth rotated about its axis in a North-South ( or South-North) direction instead of an East-West one as it currently...

I attempt the solution on the attachment. The answer is 0.344 litre. Do I change 7L to m, so it is 0.007 cubic meters

Hi, I will use this text for my question: https://imagizer.imageshack.com/img921/1874/nUBPY6.jpg Source: https://www.electrical4u.com/lenz-law-of-electromagnetic-induction/ The text says that when the north pole of a magnet approaches the coil, the induced current in coil is such that it...

In my current location there isn't a distinct Fall season. When I lived in the Eastern USA, Fall often put me in a quiet and melancholy mood. I read alot. In the winter, I go to bed earlier, drink more coffee, and eat more hot foods. All this has to do with the desire to be warm. Yet my...

I tried solving this question a few ways and this one logically made the most sense however I got it wrong and I am unsure of why. I first plugged in t=2 into p(t). p(2)=0.3(2)1/2+6.3 to obtain 6.724264069. I then found the derivative of D(p) which is D'(p)=-60000/p3. I plugged in...

I've attached a screengrab of the problem (Specifically, Part B, as indicated in the image) and my attempt at a solution. Summarized, my thinking was based on using ##-\Delta U=\frac{Kx_i^2-Kx_f^2}{2}##. After using up all my attempts, the solution, as it turns out, was U2=4.91J. No variation...

Okay i was reading abrikosov's book and he said since in QM spin only changes by integer values boson excitiation happens one at a time and fermion ALWAYS appears or disappears in pairs. but isn't change from a spin up to spin down 1/2 to -1/2? or i had the wrong convention which |1/2| shouldve...

Hi All Given that the Riemann Curvature Tensor may be derived from the parallel Transport of a Vector around a closed loop, and if that vector is a covariant vector Having contravariant basis The calculation gives the result Now: Given that the Christoffel Symbols represent the...

for a)##\Delta S=\mp \int_{T_i}^{T_0}\frac{C(T)}{T}dT## and ##\Delta S_{th}=\int_{T_i}^{T_0}\frac{dQ}{T_0}dT## so ##S_{univ}=\Delta S_{th}+\Delta S##. What is ##dQ## equal to ? I don't know how to answer question b). Thank you for your help.

Comparing high precision atomic clocks, one flying in a airplane and one on the ground had demonstrated permanent time dilation presumably due to special relativity (speed) and/or general relativity (gravity) . While similar experiment with a ruler would demonstrate length contraction only...

I'm releasing pressurized propellant into another chamber which is at atmospheric pressure, I want to estimate the temperature to which that chamber will drop to and the rate at which the liquid (collecting in the new chamber) will boil. The second chamber is open to atmosphere via a small...

Homework Statement: A quantity of ideal gas initially at 20 atmospheres in a volume of 1 litre and a temperature of 300K suddenly expands and comes to equilibrium with a volume of50 litres and a pressure of 1 atmosphere. If the process is irreversible and involves the transfer of heat and work...

Firstly I tried defining into an equation to make the whole thing more 'tangible'. ##m_1= Paula's~Weight⋅2 = m_p⋅2## ##m_2= \frac {Dave's~weight}{2} = \frac {m_d}{2}## Before impact ##E_k1= \frac 1 2 (m_p⋅2)(0^2)## ##E_k1= \frac 1 2 (2m_p)## ##E_k1= m_p ## After Impact ##E_k2= \frac 1 2...

So to begin this question, I do know that volume =4/3 pi r cubed, while the surface area) 4 pi r squared. I will like to clarify some things about the question: 1) does the first sentence means dv/dt is proportional to 4 pi r squared? 2) given the second sentence how am I able to construct an...

Hello, I'm using photo-sensors from commercial and industrial cameras to document an experiment. Afterwarde I evaluate the change in brightness during the test of a fixed segment of every image I took. The ambient light condition is stable and the images are in raw files, but I'm unsure how raw...

Part (a) ΔS = ∫ (dq/T) because: dq = PdV = (nRT/V)dV Then: ΔS = ∫ (1/T)*(nRT/V)dV ΔS = nR ∫(1/V) dV ΔS =nR[ln(V2/V1)] Part (b) This is where I'm stuck. I know [P + a/(v/n)2][v/n - b] = RT can be solved for P and simplified to P = [RT/(v-b)]-[a/v2] since n=1mol But I don't know how to proceed...

Homework Statement: A PV diagram shows an isobaric expansion, I'm asked to know the signs of: work done on, heat added to, and change in energy content of the system. Homework Equations: W= integral (P dV), dU = Q + W Since this is an expansion, the system does work on the surrounding and...

In relativity, the speed of light in vacuum is a universal constant. Also, it has wave-particle duality. So if the speed of light slows down in a different media other than vacuum, what exactly is slowing down? Macroscopically speaking, the speed of light does slow down. What about in the...

Popular precis: https://www.aging-us.com/dna-methylation-grimage-strongly-predicts-lifespan-and-healthspan Ake Lu, Steve Horvath David Geffen School of Medicine at UCLA My take: While DNA may change anywhere due to methylation, so that cells in a given tissue may have different damage points...

I tried modeling the problem quite a few ways. one was to say that the difference between the heat emitted by the room and the heat emitted by the bulbs would equal the heat absorbed by the room, and that could allow us to calculate temperature. This did not work. I'd appreciate your help

I am a computer science graduate working in computer vision , remote sensing field for a private company. Been studying physics on my own for curiosity(A levels, H&R books, feynman essentials) . I developed interest in physics few years back and I have been searching for ways to convert my...

Hello, I was pondering on the well known fact that a certain amount of substance, when absorbing heat, increases in temperature up to a certain temperature and then phase (state) transformation takes place. Any energy supplied at that point does not increase the temperature any further but is...

Paul Dirac proposed a hypothesis called "Large Numbers Hypothesis" (https://en.wikipedia.org/wiki/Dirac_large_numbers_hypothesis), where he basically stated that, if he was correct, laws of physics would change with time. But what about fundamental laws and constants? (Not only 'effective'...

I was measuring the water pressure on my house using a pressure gauge with a hose bib fitting. So I screwed it on and the meter read 120psi. Then I started turning the valve off and the pressure decreased the more I closed the valve. There was no flow downstream of the valve (or anywhere...