System Definition and 1000 Threads

PART B ONLY: The cylinder undergoes torque when the mass m2 is removed: τNET = Iα = FNETr = 45α = FT(0.5) FT = 90α, therefore msystem = 90 kg After this step, I am not sure what to do. τ = ΣF = Fg - Ft = ma = (20 kg)(9.8 m/s2) - (90α) = 196 -...

The system is in rotational equilibrium and therefore experiences no net torque, meaning all individual torques must add to zero. τNET = 0 = FFTsin(θ)L - FgL - Fg(L/2) τNET = 0 = FTsin30°(0.6?) - (0.5)(9.8)(0.6) - (2.0)(0.6/2) My only problem (I think) is figuring out what the length L is for...

so far I have found the velocity 1 and 2 by dividing the volume flow rate over the area which I got from pi x dia squared/4 my v1 = 1.01859m/s and v2= 2.82942m/s i have then figured out a pressure for the 15mm pipe which i got an answer of 2.71 bar however i am stuck on the rest of the question...

In light of the modern definition of what is a coordinate system, namely it's a pair (U, f) with U a region of a m-dimensional manifold, and f a bijection from U to ##\mathbb R^m##, can we say that the polar coordinates on ##\mathbb R^2## are a coordinate system? I was thinking about this and...

Homework Statement In A spring mass system , the spring stretches 2 cm from its 's frelength when a force of 10 N is applied . This spring is stretched 10 cm from it's free length , when a body of mass m = 2 kg is attached to it and released from rest at time t = 0 . Find the A) force constant...

Hi PF! I have a tricky problem that I'm trying to model, and none of the typical textbook examples cover this--or they only cover it tangentially--so I was hoping to get some insight here. (Couldn't find a "Thermodynamics" section of the forums so if there's a better place to post this, please...

If the distribution of elements in the universe is also the distribution of elements in the solar system for regular matter, and being dark matter so overwhelmingly prevalent in the universe, why can't we see it overwhelmingly in the solar system?

Hi. After some study, I came across symmetrical components. I found the attached schematic below on the internet, and will use it to explain my question. Question: Imagine that a single-line to Earth fault occur in one of the phases, i.e. resulting in an unbalanced system (we assume it was...

It is known that the center of mass of an isolated system will assume the same location no matter what internal forces there are (as long as no net external force occurs). My first question is if there exist two bodies of masses m1 and m2 in some space that has no friction, gravity, or...

Homework Statement I am carrying out a regression for diameter of a part Homework Equations Diameter = -0.0531052 + 0.0443237 * exp (-0.0103633 * 'Time elapsed') if diameter is -0.052 then can some one please calculate the value for time elapsed would you please explain the steps The...

Hi PF! Given the ODE system ##x'(t) = A(t) x(t)## where ##x## is a vector and ##A## a square matrix periodic, so that ##A(t) = A(T+t)##, would the following be a good way to solve the system's stability: fix ##t^*##. Then $$ \int \frac{1}{x} \, dx = \int A(t^*) \, dt \implies\\ x(t) =...

Homework Statement A block is suspended by an ideal spring of the force constant K. If the block is pulled down by applying a constant force F and if maximum displacement of the block from its initial position of rest is X then, find the value of X. Homework Equations mg + F = XK + K(mg/K)...

Homework Statement I have a question about the pulley problem in the attachment. Homework Equations This question can be answered using equilibrium of forces, namely Fx = 0 and Fy = 0. The Attempt at a Solution The answer key states that for the sum of the x-components, we should use the...

Hi! I'm working in a new area and I'm looking for inputs/suggestions for relevant factors to look into and possible ressource where I can read about this :) I did some tests in a pulley similar to the one below. I had a fixed weight at M2. I started with M1=M2 but added weights to M1 until...

Homework Statement I need to solve a system of two equations for T and θ algebraic and with all the other parameters known. φ is equal to: Homework Equations The relevant equations are the two equations left of * in the image below The Attempt at a Solution I tried Gauss elimination but I...

$$x_0\cos(\phi) = 2.78$$ $$x_0\sin(\phi)=2.78 \left( \frac{\gamma^2/2}{ \sqrt{10-\frac{\gamma^2}{4}}} \right)$$ $$x_0e^{-15\gamma} \cos\left(30\sqrt{10-\frac{\gamma^2}{4}}-\phi\right)=1$$ I don't know awsner of $$\phi , x_,\gamma$$

Homework Statement [/B] I have a metal disc adhesively bonded at its edges to a piezoelectric ring. The piezoelectric ring vibrates radially which leads to the plate vibrating transversely. I am looking to work out the resonant frequency of the metal disc which I believe will depend on the...

Homework Statement Homework Equations F = ma The Attempt at a Solution I couldn't draw the freebody diagram. There's this weight of mass m, which is mg, downwards from m and there's tension T to upwards. This T affects mass M in the +x direction, but how could i find out the normal force...

Hi, I have a question regarding the tragic crash of the latest 737 Max. Is it not a huge error in the flight laws and the MCAS software to execute a nose down maneuver at any altitude? Should the system not have a rule to prohibit such a maneuver below a minimum altitude threshold? I'm also...

Hi everyone, I am researching how numerical simulations have evolved over the years in nuclear reactors for assessing the thermal hydraulics inside the reactor core. I have found vague information in regards to the three different main numerical techniques but want to learn more. So far...

Hello, I'm having a problem with this system. Ignore the physics. I have the feeling it should be tremendously easy... but I can't figure it out. I don't know how to extract it from the pdf so I'll post just the these 2 pages. https://ufile.io/39ovq The equations are (1.14) and (1.15), the...

Hello, I am attempting to expand my physical understanding of some engineering principles I’ve learned during my first semester of ChemE. I am making a small plastic car that will be propelled with a weak fan. I am attempting something similar to a ChemE project car. Is there a way I can use a...

**Reposting this again, as I was asked to post this on a homework forum** 1. Homework Statement Hi, I am trying to solve this math equation (that I found on a paper) on finding the variance of a noise after passing through an LTI system whose impulse response is h(t) X(t) is the input noise...

Homework Statement Given the picture: Make the free body diagrams of each body and the pulley. Remember that there are two different strings therefore there are two different tensions.Assuming that the mobile of mass M starts from rest and has a displacement D at a time t, and the bodywith...

Homework Statement (It should be noted that the actual problem has specific values associated with a, b, and c. However, at this point I'm trying to find a method to solve the problem rather than a specific solution). Homework Equations The Attempt at a Solution When I was trying to solve...

Hi, I am trying to solve this math equation on finding the variance of a noise after passing through a system whose impulse response is h(t) X is the input noise of the system and Y is the output noise after system h(t) if let's say variance of noise Y is σy2=∫∫Rxx(u,v)h(u)h(v)dudv where...

Hello my fellow scientists! This is my first post on this forum, but most certainly not my last. I am relatively new to physics. I mean, i understand the basics. I would like to make it my hobby. You know, really find a passion for the physics. BTW, i am from the Netherlands, so please do not...

Homework Statement A capacitor consists of two large metal disks placed a distance ##s## apart. The radius of each disk is R ## (R \gg s)## and the thickness of each disk is ##t##. The disk on the left has a net charge of ##+Q## and the disk on the right has a net charge of ##-Q##. Calculate...

Homework Statement Two charges, ##-q_1## and ##q_2## are fixed in the vacuum and separated by a distance ##a##. What should be the velocity ##v## of a particle with mass ##m## and charge ##q##, traveling from an infinitely far point along the line which unites ##q_1## and ##q_2## in order to...

Homework Statement Could someone look through my work? The parts where I wrote (??) are steps I am especially unsure about. Many thanks in advance. A large reservoir at temperature ##T_r## is placed in thermal contact with a small system at temperature ##T##. They end up at temperature...

What are the precise conditions for thermodynamic equilibrium? I know that a system in thermodynamic equilibrium must have constant temperature and that there can be no net macroscopic flow of energy or matter. However, is it possible for there to be a system in equilibrium that has a spatially...

Hello all, I am in deep water here based on my very fundamental understanding of physics generally and solar design specifically. I am 83 years, homeless, and have access to land with one building, wood heat, non-potable site water, and nothing else. I want to make a PV system with an array...

Can the universe be treated as a thermodynamic isolated system? And why?

I have equation system: x + y + z - a*k = 0 -b*x + y + z = 0 -c*y + z = 0 -d*x + y = 0 where: a, b, c, d = const. Have to find: x, y, z, k Attempt of solution: I create Matrix A with coefficients; Matrix B - Solutions (Zeros) and Matrix X - variables. When I try to use Cramer's rule -...

Hello all, I have the "correct" answer from Chegg. However, I am not satisfied that I really understand. Heres the problem: Determine if the system is consistent. Do not completely solve the system. 2X1-4X4=-10 3X2+3X3=0 X3+4X4=-1 -3X1+2X2+3X3+X4=5 Here is my attempt: I first write the system...

Homework Statement An isolated parallel-plate capacitor of area ##A_1## with an air gap of length ##s_1## is charged up to a potential difference ##\Delta V_1## A second parallel-plate capacitor, initially uncharged, has an area ##A_2## and a gap of length ##s_2## filled with plastic whose...

Homework Statement [/B] Two blocks A and B of masses m and M are connected to the two ends of a string passing over a pulley. B lies on plane inclined at angle theta with the horizontal and A is hanging freely as shown. The coefficient of static friction between B and the plane is us. Find the...

Homework Statement The system is shown in the image. In the beaded string shown in Figure 1, the interval between neighboring beads is a, and the distance from the end beads to the wall is a/2. All the beads have mass m and are constrained to move only vertically in the plane of the paper...

I'm having trouble picturing the energy states for some systems. For instance, I was reading Reif's Fundamentals of Statistical and Thermal Physics, and at some point he talks about the energy states of a pool acting as a heat reservoir interacting with a bottle of wine. The problem is that...

Hi, This is not homework. I need to understand why the binary number system works in the case of a particular problem. While trying to solve the puzzle below, I set out to finding the minimum number of denominations required to create a particular amount. To create any amount up to $15, I just...

Hello! I am a materials engineering BSc student currently writing my bachelor thesis. The topic of my thesis is regarding the PV/T system and the best material choice for the interface between the glass/glass PV module and the heat mat. I would appreciate any ideas for material with best thermal...

Hi, I somehow carelessly installed Python 3.72, 32-bit in my 64-bit system. Is this a workable situation or will I pay a price eventually in a conflict between 32-bit software living in a 64-bit system? Should I uninstall and reinstall a 64-bit version?

While @BillTre wrote about how scientists are trying to use the adenovirus in treating retinoblastoma, another team has published that the macrophages in the immune system can themselves engulf cancerous cells. Macrophages have the power to engulf and destroy cancerous cells, but tumour cells...

Homework Statement [/B] A 4 kg mass slides 2 m over a horizontal surface with force of kinetic friction of 2N, initial velocity is 5 m/s. Find it's final velocity. My problem... we've been asked to solve this problem using the Work-Energy theorem, and we've been given it in the form of: W =...

Homework Statement Sorry for all the posts lately. This should be the last one for a while. Solve the following system of linear equations: ##\displaystyle 4x-y=10## ##\displaystyle x+y-3z=8## ##\displaystyle 3x-y+z=12## Homework EquationsThe Attempt at a Solution [/B] I started with...

I've a system of partial diff. eqs. in thermo-elasticity, I can solve it using normal mode analysis method but I need to solve it using laplace or Fourier

How to prove the dipole moment of an isolated quantum system in isotropic space is identically equal to zero, unless there exists an accidental degeneracy. Thanks in advance

In one dimensional system the boundary condition that the derivative of the wave function Ψ(x) should be continuous at every point is applicable whenever?

MODERATOR'S NOTE: HOMEWORK INCORRECTLY POSTED TO CLASSICAL FORUM, SO NO TEMPLATE I need help with the following question: Please have a look at the question and my attempt at the solution. Alternative cooling systems are considered for a large computing centre requiring 1 MW of cooling...

I’m looking to create a self sustaining ecosystem inside of a 4x2’ glass box that could be a totally closed system (with the exception of heat transfer, I can’t really prevent that). The idea is that I would bury it for a year and then dig it up again. In order for that to work I would need a...