Recent content by heyhey281

My professor said that F is not additive, meaning F ≠ F1 + F2, where F1 is the helmholtz energy of system 1 and F2 is the helmholtz energy of system 2. So my question is, how can I decide wether a thermodynamic potential (F, H, G) is additive or not?

The time scale on which the change (such as a change in external parameters or a external parameters or an addition of heat) takes place is referred to as τ_exp. The relaxation time τ_relax, on the other hand, is the time that the system needs to return to a state of equilibrium after a sudden...

Ideal gas: If the gases are of different type, I would say the entropy stays the same. The total entropy is in both cases just the sum S = S1 + S2, where S1 is the entropy of the first gas and S2 the entropy of the second gas. If the gases are of the same type, I think the entropy change is also...

I get that the relative fluctuations of extensive properties (in thermodynamics) are tiny because you can divide the whole system in many subsystems and apply the central limit theorem, but I just dont get it with intensive properties. Could someone explain?

but why is ##\dot m## effectively constant over the interval ξ? I never said that ξ is an infinitesimal time interval, it could be for example 5 seconds?

Yes sure. ξ is a constant in the equation and is an arbitrary time step. Think of it as Δt. (Δt > 0) After a certain time ξ, the momentum is the rocket times its velocity and the mass times its velocity, which is ejected downward. At the time t + ξ, however, one must take into account that...

My reasoning was this: After a certain time ξ, the momentum is the rocket times its velocity and the mass times its velocity, which is ejected downward. At the time t + ξ, however, one must take into account that mass which was ejected at the time t has a higher velocity than particles which...

I tried to use conservation of momentum I only want to know if the equation I came up with is correct and if not, why?