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

Problems 453

Problems

14.1. Using the Excel Helpmenu, discuss how the following

functions are used. Create a simple example and dem-

onstrate the proper use of the function.

a. TRUNC(number, num_digits)

b. ROUND(number, num_digits)

c. COMBIN(number, number_chosen)

d. DEGREES(angle)

e. SLOPE(known_y’s, known_x’s)

f. CEILING(number, significance)

14.2. In Chapter 20, we will cover engineering economics. For

now, using the Excel Helpmenu, familiarize yourself

with the following functions. Create a simple example

and demonstrate the proper use of the function.

a. FV(rate, nper, pmt, pv, type)

b. IPMT(rate, per, nper, pv, fv, type)

c. NPER(rate, pmt, pv, fv, type)

d. PV(rate, nper, pmt, fv, type)

14.3. In Chapter 10, we discussed fluid pressure and the role of

water towers in small towns. Recall that the function of a

water tower is to create a desirable municipal water pressure

for household and other usage in a town. To achieve this

purpose, water is stored in large quantities in elevated tanks.

Also recall that the municipal water pressure may vary from

town to town, but it generally falls somewhere between 50

and 80 lb/in

2

(psi). In this assignment, use Excel to create

a table that shows the relationship between the height of

water above ground in the water tower and the water pres-

sure in a pipeline located at the base of the water tower.

The relationship is given by

where

Pthe water pressure at the base of the water

tower in pounds per square foot (lb/ft

2

)

rthe density of water in slugs per cubic foot,

r1.94 slugs /ft

3

gthe acceleration due to gravity,g32.2 ft /s

2

hthe height of water above ground in feet (ft)

Create a table that shows the water pressure in lb/in

2

in a

pipe located at the base of the water tower as you vary the

Prgh

height of water in increments of 10 ft. Also plot water pres-

sure (lb/in

2

) vs. the height of water in feet. What should be

the water level in the water tower to create 80 psi water

pressure in a pipe at the base of the water tower?

14.4. As we explained in Chapter 10, viscosity is a measure

of how easily a fluid flows. For example, honey has a

higher value of viscosity than does water because if you

were to pour water and honey side by side on an

inclined surface, the water will flow faster. The viscos-

ity of a fluid plays a significant role in the analysis of

many fluid dynamics problems. The viscosity of water

can be determined from the following correlation:

where

mviscosity (N/s#m

2

)

Ttemperature (K)

c 1 2.414  10

 5

(N/s#m

2

)

c 2 247.8 K

c 3 140 K

Using Excel, create a table that shows the viscosity

of water as a function of temperature in the range of

0 C (273.15 K) to 100C (373.15 K) in increments of

5 C. Also create a graph showing the value of viscosity

as a function of temperature.

14.5. Using Excel, create a table that shows the relationship

between the units of temperature in degrees Celsius

and Fahrenheit in the range of  50 to 150C. Use

increments of 10C.

14.6. Using Excel, create a table that shows the relationship

among the units of height of people in centimeters,

inches, and feet in the range of 150 cm to 2 m. Use

increments of 5 cm.

14.7. Using Excel, create a table that shows the relationship

among the units of mass to describe people’s mass in

kilogram, slugs, and pound mass in the range of 20 kg

to 120 kg. Use increments of 5 kg.

14.8. Using Excel, create a table that shows the relationship

among the units of pressure in Pa, psi, and inches of

water in the range of 1000 to 10,000 Pa. Use incre-

ments of 500 Pa.

mc 110

c 2 / 1 Tc 32

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