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Sahil Dev
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Homework Statement
Understanding the first law of thermodynamics
Homework Equations
The Attempt at a Solution
[/B]I have been doing a self-study course on heat transfer. I have been reading from the book by Incropera and all.
I understand that the first law of thermodynamics forms the very basic as fundamentals like the conduction equation are all derived from the fist law.
I have a few questions concerning the first law of thermodynamics and shall be grateful if helped. I understand that some might advise to do a complete course on thermodynamics first before heat transfer course. Surely, I will but need to look into basics of heat transfer a bit urgently.
Concerning the first law of thermodynamics;
We first have the first law of thermodynamics for a closed system being stated as;
Firstly, the first law of thermodynamics addresses the ways in which energy can cross the boundaries of a system.
- For a closed system (a region of fixed mass), there are 2 ways: heat transfer through the boundaries and work done on or by the system.
i.e. the change in the total energy stored in the system is equal to the net energy transferred to the system minus the net work done by the system
I have got the following questions here;
a) What is a closed system? Is it a system- from the boundaries of which mass cannot leave (hence the term closed) ?
b) Secondly, can anyone give a physical simple example of a closed system?
c) What you mean by work done by the system? Any example will be really helpful
We then say that the first law of thermodynamics can be applied to a control volume (or open system), a region of space bounded by a control surface through which mass may pass. Mass entering and leaving the control volume carries energy with it; this adds a third way energy can cross the boundaries of a control volume.
d) I have a little confusion again. Above it is said, for an open system we have a THIRD way energy can pass through the control volume.
I am not very clear with the three ways energy can pass through the system. What exactly are the 2 ways in the closed system and third way in the open system that define how energy can pass through the system?
Please can anyone help? I shall be really grateful
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