work

[megangeorge-1K]

If we are calculating work on a system and W is a positive number, does that mean work is done by the system or work is done on the system? What is the difference between these two?

[Christopher Tran 1J]

Work is being done on the system when w is positive, since the internal energy (U) of the system increases.

[Daniel Lai]

It means work is being done on the system.

[Stevin1H]

When the value of w is positive this means work is being done on the system (ex. is compression). This is because the formula for work is w=-PdeltaV so when there is compression from work being done on the system, the negatives will cancel out and the w becomes positive. Therefore, when work is being done by the system, this is a negative value because of expansion.

[MadelynNguyen1F]

The work done on the system will be positive if a system is compressed and delta-V is negative

[Lopez_Melissa-Dis4E]

When work is (+), then work is being done ON the system.
When work is (-), then work is being done BY the system.