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

In the Chapters 7 and 8, we explained the role of length, time, and length and time

dependent quantities such as area, volume, speed, volume flow rate in engineering

analysis and design. The objective of this chapter is to introduce the concept of mass

and mass-related quantities encountered in engineering.We will begin by discussing

the building blocks of all matter,atoms and molecules.We will then introduce the

concept of mass in terms of a quantitative measure of the amount of atoms possessed

by a substance.We will then define and discuss other mass-dependent engineering

quantities,such as density,specific gravity,mass moment of inertia,momentum,

and mass flow rate.In this chapter,we will also consider conservation of mass and

its application in engineering. Table 6.7 is repeated here to remind you of the role

of fundamental dimensions and how they are combined to define mass-dependent

variables such as moment of inertia, momentum, and mass flow rate.

230 Chapter 9 Mass and Mass-Related Parameters

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
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