Work done on/done by the system
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Work done on/done by the system
In the equation for work, can we assume the answer is always the work done by the system, not on the system?
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Re: Work done on/done by the system
Essentially if the work is done by the system it's sign will be negative and if work is done on the system its sign will be positive.
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Re: Work done on/done by the system
Usually the question will ask for the work by the system, but it could be asking for the work done on the system, so it's best to not assume anything & read the question carefully.
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Re: Work done on/done by the system
For most of the questions we do, we can assume that work is done by the system unless otherwise specified. The sign for work (positive or negative) is also an indicator of whether work is done on or by the system, with negative meaning that work is done by the system.
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Re: Work done on/done by the system
I think it would depend on the question. It's best to remember that work done on the system would be positive as the temperature of the surrounding environment is greater than the temperature of the system, and work done by the system would be negative since heat would be leaving the system.
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Re: Work done on/done by the system
To follow up, it definitely depends on what the question is asking, but when you are trying to differentiate just remember that when work is done by the system the change in volume will be positive because volume is increasing meaning that the system is losing energy in the form of work making work done by the system a negative value.
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