# Search results

1. ### Motion due to gravity without neglecting varying distance

Hello everyone. In an attempt to brush up my Calculus skills and apply them to a physics problem, I made up an excercise which I tried to solve, but got stuck in the process. I'll write my attempt at a solution and I'd be grateful if someone could correct my approach and maybe even help me...
2. ### Thermodynamics - Irreversible Adiabatic expansion

Homework Statement Closed system made of a cylinder containing air, compressed by a piston with weights on top of it. The piston is frictionless and its weight can be neglected. The system contains initially 10 kg of air at 27 °C and a pressure of 10 ata. The weights are suddenly halved...
3. ### Why is Flow Work defined as pV and not pdV?

In the chapter relative to First law applied to flow processes, my book explains the "Flow Work" which appears in the energy balance, as work needed to push a volume of fluid into (and out of) the control volume. It also says that it's equal to pV, and then it is added to the internal energy U...
4. ### First Law of Thermodynamics for Irreversible Processes

Hello everyone. I have found quite a lot of conflicting information about the first law applied to irreversible processes and in particular whether the dS term in the equation dU = TdS - pdV only accounts for the entropy transferred or for the total entropy, i.e. dS_transferred + dS_created...
5. ### Differential form of the first law of thermodynamics

Hi everyone, I'm new here. I'm an italian student who has an exam in applied thermodynamics soon. Through the whole course as well as the Physics one I have faced a lot of equations expressed with differentials, basically all of them. I have never been taught how to use them though. For...