## Work

$\Delta U=q+w$

605136321
Posts: 85
Joined: Wed Sep 18, 2019 12:19 am

### Work

When is work positive/negative

Jessica Castellanos
Posts: 102
Joined: Sat Aug 24, 2019 12:17 am
Been upvoted: 1 time

### Re: Work

When a system does work, work is positive
When work is done on a system, work is negative

RasikaObla_4I
Posts: 100
Joined: Thu Jul 25, 2019 12:15 am

### Re: Work

when something is being compressed, work is done by the system, so it is positive. When something is expanding, work is done on a system, so it is negative.

SimranSangha4I
Posts: 99
Joined: Sat Sep 14, 2019 12:17 am

### Re: Work

Positive would occur when the work is actually able to be done. When there is work being done on the system itself, the work would actually be negative.

Matthew Chan 1B
Posts: 111
Joined: Sat Sep 07, 2019 12:16 am

### Re: Work

When there is work done on a system, the work is negative. However, when the system itself does work, then work is positive.

Matthew Chan 1B
Posts: 111
Joined: Sat Sep 07, 2019 12:16 am

### Re: Work

Matthew Chan 1B wrote:When there is work done on a system, the work is negative. However, when the system itself does work, then work is positive.

Sorry, I meant it the other way around haha! Work is negative when the system does work. When the system has work done on it, then work is positive. Sorry about the typo!

Eesha Sohail 1D
Posts: 100
Joined: Sat Aug 17, 2019 12:16 am

### Re: Work

In relation to gases, work is done on the system when compression occurs, and the system does work when expansion occurs. The former is positive and the latter is negative.

Posts: 50
Joined: Mon Jun 17, 2019 7:24 am

### Re: Work

In thermodynamics, work is the energy transferred from the system to the surroundings. So, when the system transfers energy to the surroundings by doing work, the work is negative. When the surroundings transfer energy to the system by doing work on it, the work is positive.

Hussain Chharawalla 1G
Posts: 100
Joined: Sat Jul 20, 2019 12:15 am

### Re: Work

An exception to the expanding concept is when the external pressure is 0. Then, a system can expand without doing any work (w=0)

305421980
Posts: 101
Joined: Sat Sep 07, 2019 12:16 am

### Re: Work

When work as done on a system it is positive (because its like taking in work potential by having work done on it). When a system does work then the value is negative (because there is an output of work, like when a reaction is exothermic and releasing heat and the heat or enthalpy value is negative).

Juana Abana 1G
Posts: 100
Joined: Wed Sep 18, 2019 12:15 am

### Re: Work

When a system does work then work is positive, but when work is being done on a system then work is negative.

Jesse Anderson-Ramirez 3I
Posts: 54
Joined: Thu Sep 26, 2019 12:18 am

### Re: Work

Work done on the system is positive. Work done by a system is negative.

Ian Morris 3C
Posts: 101
Joined: Wed Sep 18, 2019 12:18 am

### Re: Work

on system= positive, by system=negative

Anish Natarajan 4G
Posts: 51
Joined: Thu Jul 25, 2019 12:16 am

### Re: Work

If the system is doing work on the surroundings, like when the volume of something is expanding or heat is being released; but if something is being compressed or heat is being put in, then the surroundings are doing work on the system.

AronCainBayot2K
Posts: 101
Joined: Fri Aug 30, 2019 12:17 am

### Re: Work

Work done on system is positive, work done by the system is negative.