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## Main Question or Discussion Point

I have little confusion about understanding a lecture note for calculation of work done by a expansion of gas.

According to text, Work done against a force w= - Fx

So work done on the system by surrounding when piston moving w = - P(external)(power exert by outside force on the piston) . X

but I did not get this one.

Work done by the system on surrounding. According to text

W' = -Fx

I did not get this point (minus in front of F) as what ever force exert by system on should be in the direction of movement and in this case exact opposite of - P(external) Am I right? ) but equation gives the right answer i.e w'= - (- P(external))x= P(external )X . In-contrast my one is incorrect

Can somebody help me out to clear this . Thanks for your time in advanced

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Report to moderator 68.228.44.236

According to text, Work done against a force w= - Fx

So work done on the system by surrounding when piston moving w = - P(external)(power exert by outside force on the piston) . X

but I did not get this one.

Work done by the system on surrounding. According to text

W' = -Fx

I did not get this point (minus in front of F) as what ever force exert by system on should be in the direction of movement and in this case exact opposite of - P(external) Am I right? ) but equation gives the right answer i.e w'= - (- P(external))x= P(external )X . In-contrast my one is incorrect

Can somebody help me out to clear this . Thanks for your time in advanced

Modify message

Report to moderator 68.228.44.236

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