phy p4 small doubt

[princesszahra]

work done on the systm is -ve or +ve?

 

[balalika]

its +ve

 

[nannes]

Negative...

 

[nannes]

@balalika Work done by the system is positive

 

[princesszahra]

@nanes
thats what she said
on the system is +ve
so other one will be -ve
thanx ppl

 

[nannes]

work done on system is negative

 

[princesszahra]

@ nanes
+ve or -ve??!

 

[nannes]

work done ON the system in negative
work done BY the system is positive

 

[princesszahra]

k thanx
!!!!!!!!1

 

[Buffer Solution]

workdone by system is negative while workdone on the system is positive..clear!!!!

 

[aristotle]

when you write the first law of thermodynamics, be sure initially the convention you apply and then stick to it through out the question
for example,
let's say that Q= ^U+^W
this is what i have adopted in this heat supplied to the system is equal to the increase in bla bla + WORK DONE "BY" THE SYSTEM .. hence work done by the system is taken positive for this convention
OR
if ^U= Q + ^W
then accordingly increase in internal energy is equal to the heat supplied + work done on the system ..
hence in this case you may say that work done takes a positive sign when it is done on the system !!
hope i have played my part

 

[mista.lova.lova]

@nannes:
u r totally wrong boi..... On the system is + ve
by the system is -ve

sharam nai aati dusron ko confuse kartay waqt...ganday bachay..

 

[princesszahra]

@ mista love
koi ganda bachay nai hain!
and thanx all!

 

[mista.lova.lova]

Note: its not mista love,.......it's mista lova lova

 

[princesszahra]

NOTE; i did it by mistake
no intension!

 

[nannes]

Mate, I guess you are wrong. Check out Pacific Physics Vol.1 page 472

Theres this whole table given.
Work done on System is negative
Work done by system is positive

 

[nannes]

:S

 

[mista.lova.lova]

oh i see that in there.....
dude, what the equation there is, delta Q = delta U + delta W

the actual eq quoted everywhere is delta U = Q + delta W

u r rite in ur own way, bt believe me even in past ppr questions, increase in int energy of a system is equal to heat suplied to system and work done on the system U = Q + W

 

[nannes]

No mate.We have been taught that the first is delta Q=delta U + delta W

 

[sse2010]

dude u migh hav been taught dat..but CIE normally follows U=Q+W....check it in past pprz too!!