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

In the previous chapter,we considered the role of length and length-related parame-

ters such as area and volume in engineering analysis and design. In this chapter,we

will investigate the role of time as a fundamental dimension and other time-related

engineering parameters,such as frequency and period.We will first discuss why the time

variable is needed to describe events,processes,and other occurrences in our physical

surroundings.We will then explain the role of periods and frequency in recurring,or

periodic,events (events that repeat themselves).A brief introduction to parameters

describing traffic flow is also given in this chapter.Finally,we will look at engineer-

ing variables that involve length and time,including linear velocities and accelerations

and volume flow rate of fluids.Rotational motion is also introduced at the end of this

chapter. Table 6.7 is repeated here to show the relationship between the contents of this

chapter and other fundamental dimensions discussed in other chapters.

TABLE 6.7 Fundamental Dimensions and How They Are Used in Defining Variables that Are Used in Engineering Analysis and Design

Fundamental

Dimension Related Engineering Variables

Length (L) Radian , Area (L^2 ) Volume (L^3 ) Area moment

[Chapter 7] Strain of inertia (L^4 )

Time (t) Angular speed ,

[Chapter 8] Angular acceleration Volume flow rate

Linear speed ,

Linear acceleration

Mass (M) Mass flow rate , Density ,

[Chapter 9] Momentum Specific volume

Kinetic energy

Force (F) Moment (LF), Pressure ,

[Chapter 10] Work, energy (FL), Stress , 1

F

L^22

1

F

L^22

1

ML^2

t^22

1

L^3

(^1) M 2
ML
t^2
1
M
L
1 32
M
t^2
1
L
t^22
1
L
t^2
1
L^3
(^1) t 2
1
t^22
1
1
t^2
1
L
L^2
1
L
L^2
Linear impulse (Ft), Modulus of Specific weight ,
Power elasticity ,
Modulus of
rigidity
Temperature (T) Linear thermal expansion Volume thermal
[Chapter 11] expansion
Specific heat
Electric Current (I) Charge (It) Current density
[Chapter 12] 1
I
L
22
1
FL
MT^2
1
L^3
(^1) L (^3) T 2
L
LT^2 ,
1
F
L^22
1
F
(^1) L 22
FL
t^2
1
F
L^32
204
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