What is the equation for adiabats in a P-V plane?

  • Thread starter Thread starter moonman
  • Start date Start date
  • Tags Tags
    Thermodynamic
AI Thread Summary
The discussion revolves around finding the equation for adiabats in the P-V plane, emphasizing that an adiabat represents a process with no heat transfer. Participants clarify that in an adiabatic process, the work done equals the change in internal energy, and the equation of state should relate pressure and volume. There's confusion about how to express this relationship mathematically, particularly regarding the role of temperature changes. The conversation suggests that understanding the internal energy equation and its dependence on pressure and volume is crucial for deriving the desired equation. Overall, the focus is on clarifying the mathematical representation of adiabatic processes in thermodynamics.
moonman
Messages
21
Reaction score
0
I have in front of me an equation for energy in a system [ U=U(P,V) ]. I'm being asked to find "the equation of the adiabats in the P-V plane". What are they looking for? I know an adiabat is a system with no heat transfer, meaning that the energy of the system would equal the work done on the system. But what is this equation that they are looking for?
 
Physics news on Phys.org
well, I'm guessing that if you have U in terms of P, V, solve for P and substitute \Delta U =C_v \Delta T for U (first putting it in the form \Delta U)...the equation of the P,V graph? An equation for P?
 
I don't think that will help with anything. If it's an adiabatic process, deltaT will be zero.
 
no, for an adiabatic process q is zero, the work of an adiabat is equal to the change in its internal energy, the work is equal to constant volume internal energy, the equation I've shown above.

you better get studying

also post the exact problem
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top