What is Closed system: Definition and 84 Discussions

A closed system is a physical system that does not allow transfer of matter in or out of the system, though, in different contexts, such as physics, chemistry or engineering, the transfer of energy is or is not allowed.

View More On Wikipedia.org
1. Change in closed system energy with both conservative and non-conservative forces

Thus $$\Delta K=-\Delta U + W_{nc}$$ $$W_{nc}=\Delta K+\Delta U=\Delta E_m$$ My question is about the following statement The system is closed. ##\Delta E_{system}## does not necessarily have to be zero. Where does (1) come from?
2. B Conservation of Angular Momentum - Problem understanding this scenario

Hello, As far I know, in a closed system both, linear and angular monentums, are conserved. İmagine such a scenario: everything is motionless, both momentums zero initially, then from a disk are fired (compressed spring push) two equal mass balls at same speed but opposite direction. Now balls...
3. Change in temperature of air in a closed system

Looking at the given values, I thought the specific heat formula could be used to calculate the final temperature of the air: c = Q/mΔT. Since the final temperature is the sum of the initial temperature and the change in temperature, the formula can be rearranged to ΔT = Q/m*c. Q = 30 W * 10 s...
4. I Pressure Required to Circulate Liquid in a Closed System?

Example: 3/4 pvc in closed circuit with pump. Linear distance of pipe=30ft / head 8ft .... so not counting friction, what general description of force can describe what's required to make the liquid circulate?
5. Physics of Water in the Closed System of the Great Pyramid

Hello, I am working on a theory for a Great Pyramid power plant and I need some help understanding if my current hypothesis is even possible and how to calculate how much water will fill the upper structure. I believe the water system to work as follows: An aqueduct delivers a steady flow of...
6. I Water bath and water vapor + air mixture in a closed system

Hello, At my work I came up with the following question: Say we have a vacuum chamber. Inside the vacuum chamber we have at the bottom a water bath. The rest of the chamber is filled with a air and water vapor mixture. The whole system is placed in a room, is at room temperature and is in...
7. Gerotor pump, will it work in a closed system without air?

just hypothetical question, First off I am not very knowledgeable in pumps. Let's say you have a pump to pump fluid, i don't think the type matters, self priming as I understand it creates a vacuum with the air in the system to pull the fluid towards the gear pumps. I'm wondering what happens...
8. J

B How is efficiency defined in rocket propulsion?

Whicle has 4 wheels, inside is oval closed room with fan that blow inside air to the wing. Wing produce difference in static pressure in direction of travel. Will vehicle move forward or not? If I look just at pressure difference at wing, vehicle will move forward but I know from Newton 3 law...
9. B Conservation of momentum in a closed system

In a closed system consisting of a set of particles not at rest relative to each other and acting on each other only by classical mechanical collision (i.e. billiard balls model, not including gravity or other long-range interactions), does conservation of momentum imply that the system will...
10. B How can the Observable Universe be a closed system?

https://www.physicsforums.com/threads/is-the-universe-a-closed-system.620503/ Hello. I was looking back at this thread from 2012 and, to be honest, I'm a bit confused. Quoting Drakkith... To our knowledge it is. At minimum you could count the observable universe as a closed system because...
11. I Stratification of air in a closed system vs the stack effect

In thinking about temperature stratification of air: I assume that in a truly closed system with no heat inputs, air would NOT stratify by temperature. On the other hand, a heat source introduced in a closed container would generate stratification while it was generating heat (and following for...
12. Solving a Closed System w/Conservative Forces: Is E1=E2 Always True?

This problem is very easy to solve considering that the two particles belong a closed system under action of conservatives force. My doubt is if it is possible to solve the problem by consider one particle by time, that is: Suppose that we know the particle m one is under gravitational force...
13. Energy interactions of a stationary closed system

A stationary closed system such as an air in a room or a water in tank can exchange energy with its surroundings, such as receiving heat, fan work, electrical work, shaft work. These energy interactions cause a change in the total energy E of a system. This total energy can be comprised of...
14. Electrical Way to generate energy in a closed system?

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...
15. Nearly Perfect Efficiency - 2nd Law of Thermodynamics

Recently read this article on Physorg: https://phys.org/news/2018-01-efficiency.html My questions are: 1. If "converting" information into energy requires a system (the demon I suppose) having a photodiode, processor, laser (light trap) all expending energy in order to cause the conversion...
16. Computation of maximum pressure in heated closed vessel

I have a relatively simple design problem but my memories of thermodynamics are very rusty and I can't figure it out on my own. To make it short, I want to put a mix of solid, water and air in a 500mL pressure vessel and heat it all up to 250'C for several weeks. T and P are at room conditions...
17. Conservation of mass relation for a closed system

Source: Çengel/Cimbala. Above part is confusing for me from some points. First of it what can a closed system refer to? I just understand a piston/cylinder arrangement with an ideal gas in it. But this concept must be more comprehensive than I have it in my mind. Second, does "closed system...
18. An ideal gas closed system reversible process

Homework Statement an Ideal gas at T = 70 C and 1 bar undergoes following reversible processes: a: Adiabatically compressed to 150 C b: then, cooled from 150 to 70 C at constant pressure c: finally, expanded isothermally to the original state (T=70 C and P = 1 bar) Homework Equations...
19. Thermodynamics piston-cylinder closed system

Homework Statement An insulated piston-cylinder device contains 5 L of saturated liquid water at a constant pressure of 175 kPa. Water is stirred by a paddle wheel while a current of 8 A flows for 45 min through a resistor placed in the water, If one-half of the liquid is evaporated during this...
20. I Open or closed Casimir system?

If you had the Casimir effect pushing two plates together, would that be an open or closed system? And why? I haven't been able to find a satisfying answer/explanation to that.
21. Compressibility/Expansion in a closed system

Howdy. Long time reader first time posting. Usually try to solve these problems on my own but this one has caused a few sleepness nights already so looking for some insight. The attached shows a simplified schematic of what I am dealing with. It is basically a hydraulic cylinder with the...
22. I Can Temperature Changes Alter Humidity in a Completely Filled Closed System?

We know that for a closed system, isobaric heating decreases the humidity and isothermal compression increases the humidity. But assuming that we start with the volume completely filled with humid air, is it not true that any increase in temperature must also increase the pressure? If so...
23. B Does QM allow for entropy decrease of a closed system?

I recently posted a statement that according to the 2nd law of thermodynamics, entropy always increases in a closed system, no matter how small the time interval is that one looks at. I think that is true for classical thermodynamic models, please correct me if I am wrong. Does quantum...
24. Heat transferred into a closed system

So i am making a simple demonstration of ideal gas law using a cylinder piston system, heating the system so the piston is pushed up, i wanted to calculate the heat transferred into the system, will it be Cp(Tf-Ti) or Cp(Tf-Ti)+ work done by the system ?
25. Thermodynamics (Closed System) questions

If I have a closed system where mass is conserved, what constraint will this bring on the system in terms of infinitesimal quantities. What conclusions can I then draw about the phases at this kind of equilibrium? Suppose we had an isovolumic, isothermal change, how would I have to alter my...
26. First law of thermodynamics applied to a closed system

Homework Statement - A well insulated rigid steel tank contains water (only) - A resistance heating element (240V, 3.67Amp) designed to heat the water as well as inlet and outlet valves for - the water. - At state-1, the water is in a saturated liquid-vapor mixture state at P(abs)=100kPa...
27. Closed system Energy transformation

Lets suppose we have a close system.In this system we have a particles.The total mass of particles is M. The total energy of system will be ##E_x+E_M=E_t## (I made the system like this) Here ##E_x## is just energy,its not important.##E_m## is the energy of masses.Now I want to move this...
28. Pump Head & Suction (leaky closed system) PF Newbie

Hi physicists! I am scratching my head to remember the most basic laws of fluid flow while I try to irrigate things from a barrel. Not exactly rocket science, I know ;-) But very exciting for me ... The situation is simply a pump (cheap submersible one) put into a barrel (sitting on the...
29. Formula for relating time and heat gained for closed system

This is for work. I need to make a table for a client. What we did: had two different closed systems, only difference is material. We had frozen goods in both containers, the containers were both removed from the cooled surroundings they were in and placed outside. The temperatures were...
30. Friction loss to vertical pipes in a closed system?

So in designing closed systems, mostly heating systems, I realized today that I've probably been doing one thing wrong all these years. In such a system one doesn't take elevation loss due to gravity into account since you "get it back" on the way down. This I've always been aware of, but what...
31. Conservation of heat on a closed system

Homework Statement Hey folks, anyone who can help me with this one get a massive shoutout. Here goes: 75 kg of water at 45 degrees celsius is "mixed" with 70 kg of Aluminum at 2600 Degrees Celsius. What is the final state of both system and how much, If any, of liquid water will be left Assume...
32. Thermodynamics - Work Done in a Closed System (Polytropic?)

Just want to check that I've used the correct method for this thermodynamics question I've been set. Any clarification would be greatly appreciated. So I have a closed system in which a gas is compressed from a pressure of 3 bar absolute to 5 bar absolute. The volume changes from 0.9m^3 to...
33. Is it practically possible to construct a closed system?

In practice, is a closed or isolated system possible? My friends keep saying No, but isn't a system inside say, a vacuum isolated? There is no outer atmosphere for transfer of energy to take place.
34. Coffee cup, bomb calorimeter: Open, closed, or isolated?

Is a coffee cup usually considered to be a closed system? Why or why not? Does it matter that steam or hot coffee may be evaporating? (I think the steam is usually considered to be an insignificant amount of matter, allowing classification to be a closed system, but am unsure.) Is a bomb...
35. Find heat loss given metabolic rate in a closed system

Homework Statement A 60 kg person is exercising in the gym, doing external work at a rate of 200W. If they have an efficiency of 20%, calculate the rate of temperature increase of their body if none of this heat was able to be transferred to their surrounds. (a) 828 ◦C per hour. (b) 13.8 ◦C...
36. Thermomystery -entropy generation in a closed system

My question relates to entropy generation in a closed system ΔS=dQrev/T for a reversible process ΔS=dQ/T + Sgen for an irreversible process This seems to suggest that Sgen arises because of the irreversibility of the heat transfer process (eg across a finite temperature difference). If...
37. Exergy Analysis of a Closed System

I was going through "Engineering Thermodynamics" by Cengel & Boles studying exergy analysis of a closed(non flow) system.Referring to the attachment as you can see the equation, δWHE=δQ(1-T0/T)=δQ-T0/T.δQ should give δQ=δWHE+T0dS (using dS=δQ/T) but in the textbook...
38. Is energy conserved in a closed system ?

If I push a book horizontally across a table I do work. But is energy conserved?
39. Liquid pressure in a closed system

Homework Statement A steel cylinder filled with water contains 3000psi of pressure, completely sealed, walls ≈ infinite thick. No gas is present inside of the cylinder, and no heat exchange. To the problem; if a solid rod/piston enters on top of the cylinder with no possibilities to bleeding...
40. Thermodynamics first law closed system

1) A rigid walled tank 5m3 contains helium at 10 bar. The cylinder is heated from 10 °C to 50 ° C. What is the work done during the heating cycle.
41. Thermodynamics 1st law question - closed system

Homework Statement 1kg of helium in a closed system has 40kj added by heating & 100kj removed by work during a reversible polytropic process. The initial temp of the gas is 300K & the initial pressure is 100kN/m2 Q. find the final temp of the gas & pressure Homework Equations...
42. Pressure increase in a closed system

Hello All, I work in the refrigeration industry, and I'm trying to put a hard number on a hypothetical situation. The situation is a lapse in SOP and liquid gets trapped in a line. For this hypothetical situation the line is 100% full. What would the increase in pressure be per degree? I...
43. Thermodynamics Closed System Energy Balance

Hi everyone, I am currently reviewing for a thermodynamics exam and have come across a difficult problem while studying. Here it is: An insulated tank containing helium, a monatomic gas, at P1t = 1000kPa and T1 = 800K is connected to an initially evacuated insulated piston-cylinder device...
44. Sealing a 6 torr closed system vacuum

I wish to design a two chamber stainless steel vacuum system where the two vacuum chambers are connected via a flexible tube with a valve. The system needs to be able to be pumped down to 6 torr and must be able to maintain that vacuum for at least a year without pumping. The size of the...
45. Can Matter Be Transferred Between Universes?

i wish to know if matter can be transferred from one universe to other universe? does our universe have valve like thing to let the matter in or out of the system?
46. Can the Entropy of an Isolated System Decrease?

So in my physics textbook, the 2nd law of thermodynamics stated in terms of entropy reads "the entropy of a closed system can never decrease." Now, shouldn't it indicate the entropy of an isolated system can never decrease. All other sources I've looked at note an isolated system, as well...
47. Pressure in a closed system using an inclined manometer

Homework Statement In the figure attached the pressure at A and B are the same 100 kPa. If water is introduced at A to increase p_A to 130 kPa find the new positions of the mercury menisci. The connecting tube has a diameter of 10 mm. Assume no change in Liquid density. Homework...
48. Water speed in the closed system

Does water speed in the pipes having the same diameter is strictly the same in any point of a closed (heating) system (with pump working) ? On the contrary, although liquids are "incompressible" in practice, however, does the piping still allows it to be so : the more far the water from the...
49. Does entropy in a closed system always increase OR remain constant (

Does entropy in a closed system always increase OR remain constant ( in equilibrium ). I have a friend arguing it is ALWAYS increasing. His latest argument was, "if no energy enters or leaves an isolated system, the availability of the remaining energy decreases."
50. Instruments and Imaging: How to prevent condensation inside a closed system?

Dewing of a mirror or object glass can be countered with various devices and methods, but its occurrence inside a closed system is particularly problematic. I have received the following enquiry (from an experienced observer who has used several instruments over many years) concerning...