## Work done on / work done by system

$w=-P\Delta V$
and
$w=-\int_{V_{1}}^{V_{2}}PdV=-nRTln\frac{V_{2}}{V_{1}}$

Tia Tomescu 2D
Posts: 42
Joined: Fri Sep 29, 2017 7:06 am

### Work done on / work done by system

Could anyone explain to me they difference between work done on the system and work done by the system? I have trouble grasping the concept of work and the system.

504754253
Posts: 45
Joined: Fri Jun 23, 2017 11:39 am

### Re: Work done on / work done by system

work done on a system means energy comes in while work done by the system mean energy is taken out

Scout_2C
Posts: 15
Joined: Fri Sep 29, 2017 7:05 am

### Re: Work done on / work done by system

When work is done BY the system, then w(work) = some NEG value.

When work is done TO the system, then w = some POS value.

Kevin Tabibian 1A
Posts: 42
Joined: Fri Sep 29, 2017 7:06 am

### Re: Work done on / work done by system

Work done on a system means that the internal energy of the system will increase, because the surroundings are placing work unto the system.
Work done by a system means that the internal energy of the system will decrease, because the system is placing work unto the surroundings.

Christy Zhao 1H
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

### Re: Work done on / work done by system

When work is done to the system, energy is added and work is positive. When work is done by the system, energy leaves the system and work is negative.

RussellChin_3A
Posts: 42
Joined: Sat Jul 22, 2017 3:01 am

### Re: Work done on / work done by system

Work done on the system means that the system is receiving the work so it is then written as +w. Work done by the system means the system is expending energy to do the work and so the work is -w.