ME 311
THERMODYNAMICS
S. Masutani
FALL 2007
Lecture I:
Introductory Concepts (Sections 1.11.3 in textbook)
•
Thermodynamics as a discipline focuses on energy.
•
Energy
, in turn, typically is related to the ability to perform work
.
•
A conceptual feeling for work
usually is derived from Newtonian mechanics via
integration of Newton’s 2
nd
Law
– what we usually see expressed as:
a
M
F
r
r
=
•
Force is a concept and hence defies definition
– has point of application;
– and direction;
– related to interaction
between bodies or entities;
– Newton’s 1
st
Law:
motion is induced by an unbalance of forces
•
1
st
law cannot be tested since forces cannot be evaluated, i.e., measured, without invoking
this law.
So what do we have?
1.
Concepts– the building blocks of any science.
– Ideas
—which tend to defy definition.
2.
To reduce mathematics–the language of science–to a tractable level, we employ models
which introduce certain simplifications and approximation of the real world.
Theory is
based on models.
– Utility of theory is restricted by idealizations made in formulating models.
3.
Finally, we have laws
which express these concepts and the theories based on models in
mathematical terms.
These laws allow man to explain and predict the physical
phenomena of the universe.
•
Laws are not absolute;
•
they are a human contrivance in attempt to understand and codify the complexities of
nature;
•
Laws are amended and extended as the complexities of models increase to encompass a
wider range of situations.
I hope during this course you will have the time to reflect upon the various formulae that
heretofore you have been compelled to memorize.
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 Fall '07
 Masutani
 Thermodynamics, S. Masutani

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