System Definition and 1000 Threads

A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and expressed in its functioning. Systems are the subjects of study of systems theory.

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  1. Wrichik Basu

    Other How faulty is the current education system?

    Having spent five months as an undergraduate with physics major, I found that there are two types of students who come to study physics: 1. For a job, and 2. For pursuing research. This thread is concerned with the second type only. Among many other problems, here are two that have concerned me...
  2. Kaelor

    Inserting thick lenses into a thin lens system and deducing values

    Homework Statement:: Finding the distance between the back surface of the first lens and the front surface of the back lens. Homework Equations:: 1/f = 1/s_o + 1/s_i I have two positive thin lenses that are separated by a distance of 5 cm. The focal lengths of the lenses are F_1 = 10 cm and...
  3. X

    I Building a solar system simulator

    Hiya Hiya. I'm trying to build a solar system simulator for research purposes, and this does not seem to be all that easy. As in, my firsts tests have the moon shooting out of the solar system... I was wondering if you folks could offer some guidance. So, since it's for research, accuracy is...
  4. M

    Engineering Design a go kart braking system

    i have been stuck on this question from my assignment, i have tried solving it in many ways, but apparently i am either bad at this or i just don't understand the question haha. * As a prudent engineer, the main shaft is now subjected to loading condition when only brake is applied. Show with...
  5. Riotto

    I Single-particle phase spaces for a system of interacting particles

    For a system of interacting particles, is it possible to define single-particle phase spaces? If not, why?
  6. nomadreid

    I Quantum state variable for entangled system

    (This question is on the elementary side...) In the Schrödinger picture, the state is dependent on time. If you have a state composed of several particles, generally you can break them up, with each one depending on local time. But in an entangled system, say of two particles, you can no longer...
  7. C

    A Use of the Stefan Boltzmann Law in a Non Equilibrium system?

    Hi everyone, I am currently trying to work something out in regards to non-equilibrium thermodynamics. If I have a block of metal in vacuum that is being heated by a laser with a constant power P, is it even possible to be able to describe the emission of radiation by the block via the Stefan...
  8. U

    Derivation of the oscillation period for a vertical mass-spring system

    I understand the derivation of T= 2π√m/k is a= -kx/m, in a mass spring system horizonatally on a smooth plane, as this equated to the general equation of acceleration of simple harmonic motion , a= - 4π^2 (1/T^2) x but surely when in a vertical system , taking downwards as -ve, ma = kx - mg...
  9. U

    Energy Conservation as an explanation for v=0 for spring mass system

    My Solution: For the displacement graph, the gradient is crucial to predict the behaviour of the displacement of the block through time. At 1: System is released - velocity is zero, considering forces acting on block, kx < mg, as block is observed to move downwards, and object is...
  10. R

    Plumbing Dingy rib automatic start syphon system

    The theory is that that the trapped air in pipe A would create enough pressure to raise the water 600 mm in pipe C, Design and parts: 32 mm x 1 metre pipe (A) running from the stern floor (open end) forward with the front end raised 100 mm, then turned 360 deg and reduced to 10 mm (pipe B)...
  11. J

    System to collect a small amount of water from the air

    Is there a well-known system that can collect small quantities of water from air, like maybe 6 oz/day? Should take up at most a cubic foot
  12. Arman777

    I Lyapunov Stability for a nonlinear system

    I am trying to understand attracting, Liapunov stable, asymptotically stable for given coupled system. I don't have any Liapunov function. Just two coupled systems such as ##\dot{x} = y##, ##\dot{y} = -4x## or sometimes normal systems ##\dot{x} = -x##, ##\dot{y} = -5y## How can I approach...
  13. PHYSICSSSTUDENT

    Conservation of energy in a bullet-wooden block impact system

    Suppose a bullet with high speed strike a wooden block and move together after collision. We know there is loss in total KE of bullet-wooden block system. The question is, if the part of the loss in KE of the bullet is transfer to heat energy, HOW to prove the CONSERVATION of ENERGY in this...
  14. jisbon

    Acceleration of masses in a pulley system

    So I figured out the equation, but it is probably wrong because the answer doesn't tally. Since the string is inextensible, I can assume that tension is the same for both sides, and acceleration for both masses is the same too So: I can say that the acceleration of 2kg block =acceleration of 7kg...
  15. B

    Length of a string over a 2 pulley system

    Hello all, I am working on a lab report for physics, and am a bit stuck on one aspect. The basic layout of the pulley system is attached. (This is a diagram I made, so if there are any inaccuracies in this one either, I am happy to fix it. So, I mostly understand the lab. My TA said, though...
  16. A

    New coordinate system and point location in new system

    hi all, firstly i need to calculate point location in new coordinate system. ı have 2 line segments and a point(x,y,z) in word cartesian coordinates system. For example, my first line segment is (0,0,5) , (50,0,3) locations and second line segment is (0,6,3),(0,-6,7) locations in cartesian...
  17. S

    Algebra Rational exponents in the real number system?

    Are there rigorous texts that treat the topic of raising real numbers to rational powers without treating it a special case of using complex numbers? I'm not trying to avoid the complex numbers for my own personal use! My goal is to determine whether students who have not studied complex...
  18. L

    Engineering How do I model a Thorium Reactor thermal system?

    Hi, I'm working on a project for a thermal fluids design class in which a theoretical Thorium reactor is to be designed and modeled, and I'm a little bit at a loss for how to start analyzing the problem. I know the system will have 4 fluid systems: an enriched FLiBe system connected via HX to...
  19. M

    How will this vibration system generally behave?

  20. Physics4Funn

    A Another question about a Causal Fermion System

    What are the specific objections to Felix Finster's Casual Fermion System besides "many objections" and "very exotic, and very, very far from mainstream"? The comment in the summary above says forget about the Dirac sea. I am sorry, but CFS is an extension of the Dirac sea idea written in...
  21. T

    Understanding energy losses in a compressed air system

    When measuring pressure drop across a compressed air system shown in the included figure, I get different results depending on the system downstream of the actual component I am measuring pressure drop across. Btw this is a real experiment that has been ran. The numbers below are different but a...
  22. Santilopez10

    Angular momentum of a mass-rope-mass system

    1) the motion equations for ##m_2## are: $$T-m_2 g=0 \rightarrow T=m_2 g$$ ##m_1##: $$T=m_1\frac{v^2}{r_0} \rightarrow \vec {v_0}=\sqrt{\frac{r_0 g m_2}{m_1}}\hat{\theta}$$ 2) This is where I am stuck, first I wrote ##m_2## motion equation just like before, but in polar coordinates...
  23. peguerosdc

    Given a set of equations, show if it is a Hamiltonian system

    Hi! So this is my first homework ever of Hamiltonian dynamics and I am struggling with the understanding of the most basic concepts. My lecturer is following Saletan's and Deriglazov's and from what I have read and from my lectures, this is what I think I know. Please let me know if this is...
  24. Frigus

    How can O- and COO- act as an electron releasing group in a π system?

    can anyone explain me how O negative and COO negative acts as electron releasing group,I understood how alkyl groups acts as electron releasing group but I can't understand this
  25. C

    Calculating the force from a pump + nozzle system

    I am attempting to calculate the force (in KgF) of a water pump + nozzle system. I have the pump curve (head vs. flow rate) for the pump, the diameter of the connection hose (2 inches) and the nozzle diameter (1 inch). The connection hose between the pump and nozzle is very short (approx 10 cm)...
  26. M

    Global Positioning System / Clocks in Space

    I'm a bit lost at how to exactly start this exercise... As far as I understand we need to first determine ##d\tau_E## and ##d\tau_S##. First question: Since we can neglect the Earth's movement, can I also neglect the movement of the satellite with respect to the far away observer? If so, I...
  27. Noor_Arnaoud

    How can I calculate the acceleration in this system?

    ma
  28. Majd64

    Finding the acceleration of a pulley system including an inclined plane

    This question showed up on my grade 12 physics test. The problem I have with this question is that I did not know the direction that the system would accelerate in, so I just solved as though the mass on the inclined plane would accelerate the system. I expected that if it would accelerate the...
  29. B

    Predicting flow rates of a pressure driven system

    Hi! I'm a student of pharmaceutical sciences which means that my physics knowledge isn’t that great ahah, if I say a big mistake in the following text, a thousand "sorrys" ahah: So, I am now writing my master thesis and currently I am finishing writing a part where fluid mechanics are...
  30. S

    Conservation of energy: a mass and pulley system

    The solution is an application of the law of conservation of energy. Start with equation (1). The masses are in equilibrium and are not accelerating. This implies that ΔK = 0, because the kinetic energy will not change without acceleration. Thus, we are left to find equation (2) in terms of θ...
  31. L

    Atwood System - max. height of the lighter object

    Magnitude of acceleration of system: a = (4.59kg - 1.71kg)(9.81N/kg)/(4.59kg + 1.71kg) = 4.48 m/s^2 Velocity of lighter mass when heavier one hits the ground: vf^2 = vi^2 + 2ad = 0 + 2(4.48m/s^2)(2.60m) vf = 4.83 m/s [up] I am not sure what to do from here? I don't really understand what...
  32. M

    How to Approach Solving a Variable-Mass System with a Falling Drip?

    S(t)= Hi all! Μy attempt to solve it: I'm stuck here. An opinion ? Thanks.
  33. D

    Increasing the 50 Ohm bandwidth of an impedance-matched system

    Hello, Some trouble came up today with designing a 50 ohm system for a wireless powering project. I'd like to increase the frequency range for which my system impedance is 50 ohms in order to reduce power losses due to mismatch. I've simulated two RLC circuits in OrCAD SPICE to demonstrate my...
  34. R

    Find the energy lost of the system of a t-shirt cannon

    I don’t even know where to start. I especially don’t know how I would find the energy inside of the pump that would then be released to shoot a T-shirt.
  35. GeorgeDishman

    I Is J0740+6620 an eclipsing system?

    It was recently announced that J0740+6620 contains what is probably the most massive neutron star found to date: https://arxiv.org/pdf/1904.06759.pdf This paper concludes the companion to the MSP is a helium-atmosphere white dwarf: https://arxiv.org/pdf/1902.11150.pdf Based on a crude...
  36. O

    RLC Circuits: Exploring Dynamic Systems

    Hi ! I'm trying to understand why does we say that RLC circuit is a dynamic system. An example of a dynamic system that i know is a pendulum. The swinging of a pendulum depends on the applied force but also on the past force. What about the output of RLC circuit ? What is the relation between...
  37. D

    Building a Planet: Considerations for a Habitable Solar System

    I am building a planet that will orbit a sun and I need help My world has 11 planes/asteroids. the planet Le Bear has multiple life forms on it. It takes 378 days to rotate around the sun. My planet has a circumference of 8199.49 miles. there are 12 months of 28 days and then 1 1/2 months of...
  38. CPW

    B Radon testing my first basement (already has a mitigation system)

    Hi PF: The house my wife and I purchased recently is our first one with a basement and it already has a radon mitigation system installed. Unfinished basement. I've sent my short-term test to the lab and I have a long-term test that I intend to start this week. Do any PF members have any...
  39. H

    A Diffusion equation and a system of equations with reciprocal unknowns?

    So the normal diffusion equation looks like \frac{\partial c}{\partial t} = k\frac{\partial}{\partial x}\left(\frac{\partial c}{\partial x}\right) I know how to get explicit and implicit solutions to this equation using finite differences. However, I am trying to do the same for an equation of...
  40. Like Tony Stark

    Pulley system with relative motion

    Well, first I tried to understand the relation between the velocities and accelerations of both bodies and I got that the velocity of ##B## is half the velocity of ##A##. This is because a change in length of the cord "that touches ##A##" must be equal to the change in length of the two cords...
  41. Student abc

    Nodes in a decentralised manufacturing system

    What is meant by the nodes of a decentralised manufacturing system? Are these the points where the manufacturing is carried out?
  42. brotherbobby

    Several parts of a system and its CM

    I have known and used this theorem for a long time solving problems ("Calculate the CM of the some given shape"). I took the theorem to be "obvious" and didn't know it could be proved (and that indeed it was a theorem at all). I can make no attempt at the proof. Any help would be welcome.
  43. B

    An ambigious optical system with ambigious solutions [JEE Adv - 20`16]

    This problem was asked in one of the most prestigious exams in India: JEE Advanced, unfortunately it was considered to be ambiguous for the scope of given examination and hence no official answer is issued for it as such.(BONUS marks to all) And so many solutions were posted on Internet which...
  44. E

    B How does this osmotic system reach equilibrium?

    [Mentor's note - this post has been edited to ask the interesting physics question while not falling afoul of the forum rule prohibiting discussions of perpetual motion] On the left is pure water (blue), and on the right is concentrated salt water (green). The red walls in the middle are...
  45. U

    I How Can I Calculate the Probability in a Multi-Level Box System?

    Good morning, I have a system that consists of a huge number of boxes, it is not important to know how many, each containing a binary number: In every cell, the probability that there is a '1' is p, so the probability that there is a '0' is equal to (1-p). What I do is take them in groups of N...
  46. A

    I Mechanical system with de Broglie-like features

    Hello, I am curious if I have this correct and if it has a name. A thin walled cylinder is spinning on its axis along its length in a closed system. It begins to draw itself in converting its invariant mass to kinetic energy. In polar coordinates ##E=\gamma_\theta m c^2, L=\gamma_\theta m...
  47. K

    Mass Transfer in a Binary Star System

    Homework Statement: A binary star system consists of M1 and M2 separated by a distance D. M1 and M2 are revolving with an angular velocity w in circular orbits about their common center of mass. Mass is continuously being transferred from one star to the other. This transfer of mass causes...
  48. CrosisBH

    Getting a solution from a system of PDEs

    I want to start off here saying I took the problem has finding a potential function, and not a general solution, so I worked to only find one function that works. I already confirmed that this function can be written as a curl of a vector function and the gradient of a scalar function. Since...
  49. TheMercury79

    I Can the Second Plane Autonomous System Have a Unique Critical Point?

    The plane autonomous system $$x' = -ax + xy\\y' = 1 - by - x^2$$ has a unique critical point when ##ab>1## Since if we set x' = 0, then either x=0 or y=a If y=a, then for y' = 0: ##1 - ab - x^2= 0## , but if ##ab>1## this leads to ##x^2<0## which has no solutions and thus ##y\ne a## The only...
  50. E

    B When to think of PE as property of a system vs of a particle

    This is a bit of a vague question, but I was wondering if someone could explain. As far as I know, potential energy is formally a property of a system (for instance, the GPE of two gravitationally attracting particles). In many physics problems it happens to be the case that one of the bodies...
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