Engineering Fundamentals: An Introduction to Engineering, 4th ed.c

A good example of an unsteady situation that is familiar to everyone is the rate of a per-

son’s physical growth. From the time you were born until you reached your late teens or early

twenties, your physical dimensions changed with time. You became taller, your arms grew

longer, your shoulders got wider. Of course, in this example not only the dimension length

changes with time but also your mass changes with time. Another common example of an

unsteady event that you are familiar with deals with the physical variable temperature. When

you lay freshly baked cookies out to cool, the temperature of the cookies decreases with time

until they reach the air temperature in the kitchen. There are many engineering problems that

are also unsteady. You will find examples of unsteady and steady processes in the cooling of

206 Chapter 8 Time and Time-Related Parameters

There is still time for you to

do some good things in life.

Once I reach the age of 20,

does my physical dimension

really become steady? What

if I were to gain mass?

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).

圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀