What is the relationship between work and pressure in a PV graph?

  • Thread starter Thread starter pulkit707
  • Start date Start date
  • Tags Tags
    Pressure Work
AI Thread Summary
In a PV graph, work is determined by the area under the curve, and when volume increases, the work done is positive. The formulas w=nRTln(p1/p2) and w=nRTln(v2/v1) are specific to isothermal processes in ideal gases. The general expression for work done in a gas is W = ∫ pdV, which applies to all processes. If the volume increases, the integral yields a positive value, indicating positive work. Thus, regardless of pressure, an increase in volume correlates with positive work done.
pulkit707
Messages
1
Reaction score
0
If in PV graph work goes down and then goes up please tell sign of work done and why?My teacher says no matter what preesure is if volume is increasing then work is positive but w=nRTln(p1/p2) and w=nRTln(v2/v1) also .
 

Attachments

  • 14482915286311339164195.jpg
    14482915286311339164195.jpg
    27.1 KB · Views: 483
Last edited by a moderator:
Physics news on Phys.org
The graph that you have shown does not correspond to the formulas you have written. Both formulas are valid only for isothermal processes in an ideal gas. For all processes in a gas, the work done is given by

W = ∫ pdV where the limits of integration are from an initial volume to a final volume. If there is an increase in the volume, then the integral is positive, and the work is positive. The integral is equal to the area under the curve, and in both parts of your diagram, the volume is increasing.
 

Thread 'Is calling fictitious forces "not real" just about terminology?'

Hi there, im studying nanoscience at the university in Basel. Today I looked at the topic of intertial and non-inertial reference frames and the existence of fictitious forces. I understand that you call forces real in physics if they appear in interplay. Meaning that a force is real when there is the "actio" partner to the "reactio" partner. If this condition is not satisfied the force is not real. I also understand that if you specifically look at non-inertial reference frames you can...
View full post »

Thread 'Derivation of Hamilton's Principle: Questions'

I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
View full post »

Similar threads

I Why work is PdV and not (P+dP)dV in an isothermal process?
Replies
6
Views
148
A Calculate the work done by pressure rupturing a spherical containment
Replies
7
Views
1K
Reversible vs irreversible work for adiabatic process
Replies
5
Views
2K
The exact formula for PV-work in an irreversible process
Replies
27
Views
9K
Final velocity of an air rifle pellet from compressed gas
Replies
4
Views
2K
Constant pressure or isobaric expansion of gas
Replies
14
Views
6K
Bernoulli's principle and work energy theorem
Replies
7
Views
3K
Use internal pressure to compute work done by an expanding gas?
Replies
15
Views
3K
How Does Pressure in a Sealed Container Change Over Multiple Cycles?
Replies
3
Views
1K
How to calculate the leak rate based on pressure drop
Replies
4
Views
5K

Hot Threads

Recent Insights

Back
Top