Sign of "Work Performed"

[Nathan Min 1I]

Recently, I solved a problem that asked for "work performed" by something (ie. negative work).

I gave the "work performed" as positive but I found out the correct answer was negative. Why is the "work performed" negative? Wouldn't the "work done on the system" be negative if the system is performing work? Should I disregard situational labels like "performed by the system" in future problems and only focus on what the correct sign would be?

Thank you!

[phiryn]

If work is done TO the system (surroundings to system) then it is positive.

If work is done BY the system (system to surroundings) then it is negative.

[David Nguyen 1K]

Work being done on a system means energy is being added from the surroundings to the system, so w should be positive. On the other hand, work being done by a system means that energy is going from the system to the surroundings, so w should be negative.