END OF COURSE STUDY GUIDE
PRINCIPLES OF ENGINEERING
1. Define the following terminology and provide a sample for each:
a. Thermal Conduction
i. The transfer of thermal energy within an object or between objects from molecule to molecule
ii. A metal spoon placed in a hot cup of soup will feel warm to your hand. The heat from the soup is
conducted through the spoon.
b. Thermal Convection
i. The transfer of thermal energy by movement of fluid (liquid or gas)
ii. Boiler heating systems circulate heat throughout a home without pumps through the use of
convection.
c. Thermal Radiation
i. The process by which energy is transmitted through a medium, including empty space, as
electromagnetic waves
ii. Heat transferred from the Sun to Earth.
d. Thermal R-Value
i. The measure of a material’s ability to resist heat
ii. The higher the R-value, the higher the resistance
e. Thermal U-Value
i. Overall heat coefficient
ii. The measure of a material’s ability to conduct heat
f. A 8 ft by 14 ft wall has an U-Value of 0.50
Btu
.
ft   F  hr
2
Calculate the heat loss through the wall if the
temperature on one side is 80 F̊ and the temperature on the other side is 65 ̊F. Be sure to show all units.
Q=UA∆T
Q=.50(Btu/(ft2xFxhr) x 112 ft2 x 15 F
Q=840 Btu/hr
g. What is the R-value of the wall? Be sure to show all units.
R=2 (ft2xFxhr)/Btu
2. Explain the difference between a series and parallel electrical circuit in function of Voltage, resistance and
amperage.
a. Series is a circuit that contains only one path for current flow. The current flowing through every series
component is equal. The total resistance (RT) is equal to the sum of all of the resistances (i.e., R1 + R2 +
R3). The sum of all of the voltage drops (VR1 + VR2 + VR3) is equal to the total applied voltage (VT). This is
called Kirchhoff’s Voltage Law.
b. Parallel is a circuit that contains more than one path for current flow. The voltage across every parallel
component is equal. The total resistance (RT) is equal to the reciprocal of the sum of the reciprocal. The
sum of all of the currents in each branch (IR1 + IR2 + IR3) is equal to the total current (IT). This is called
Kirchhoff’s Current Law.
3. Define the formulas for Electrical Current, Voltage, and Resistance along with their measuring units.
a. Current – I = V/R, measured in Amperes
b. Voltage – V = IR, measured in Volts
c. Resistance – R = V/I, measured in Ohms
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4. Describe the difference between an electrical motor and a generator.
Generators are devices that turn mechanical energy into electric energy.
Electric motors are devices that turn electric energy into mechanical energy.
5. Provide 3 samples of three machines or devices that use alternative energy systems to produce electrical power.
a. Wind Turbines
b. Solar Cells
c. Hydrogen Fuel Cell
6. Describe the mathematical equations for work, power in and power out with their measuring units for metric and UScustomary system.
a. Work = Force X Distance, measured in Joules. 1Joule=1NewtonX1Meter
b. Power In=voltage x current
c. Power Out= Work/Time, measured in Watts. One watt is equal to 1 joule of work per second
7. Calculate how much power is required to move 4 people with an average weight of 160 lbs through three storyfloors and total distance of 19ft in 4 seconds. Show your formulas and work.
Power = Work/Time and Work = Force X Distance
P= (4(160) lbs X 19 ft)/4 sec = 3040 (ft lbs)/sec
8. Calculate how much work is exerted by a conveyor belt that has a length of 4 meters and moves a weight of 50 kg
in 10 seconds. Show your formulas and work.
1 kg = 9.8 N W = F X D
W = 50kg (9.8 N/kg) X 4 m = 1960 Nm or joules
9. Explain how to calculate efficiency of mechanical and electrical systems.
a. Efficiency is the ratio of desired output energy compared to input energy.
b. For simple machines Efficiency = AMA/IMA
10. Define the following terms and provide three samples for each.
a. Renewable Energy
i. Sources that can be replaced once used
ii. Animals, Food, Biomass
b. Inexhaustible Energy
i. Sources that can never be entirely consumed
ii. Hydroelectric, tidal, geothermal, wind, hydrogen, solar
c. Non-renewable Energy
i. Sources that cannot be replaced once used
ii. Oil, coal, natural gas, uranium
d. Unreliable Energy
i. Energy sources that are not constant
ii. Solar, wind, tidal
11. List advantages and disadvantages for the following types of technology as sources of energy:
a. Solar
b. Wind
c. Geothermal
d. Fuel cell
12. Create a Venn-Diagram to compare and contrast between engineering and the engineering technology degree.
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Research
Test &
Distribution &
Complex
Evaluate
Sales
Analysis
Routine
Complex
Manufacturing
Design
Design
Production
Development
Operation,
Service, &
Maintenance
Engineering
Engineering Tech
13. Create a table with the mechanical advantage and lever classification for the following mechanisms:
Machine
Wheel and axle
Incline plane
Wedge
Pulley system
Screw
Levers
Gears
MA
IMA=Ediameter/Rdiameter AMA=FR/FE
IMA=DE/DR AMA = FR/FE
IMA=DE/DR AMA = FR/FE
IMA=# of strings last string counts if up
AMA=FR/FE
IMA=C/Pitch AMA = FR/FE
IMA=DE/DR AMA = FR/FE
Use Gear Ratio for IMA
Lever Classification
1, 2 or 3
14. Define the following terms, list their components and provide a diagram for them:
a. Open Loop System
i. A control circuit in which the system output has no effect on the control.
ii. Lacks feedback
b. Closed Loop System
i. A control system that considers the output of a system and makes adjustments based on that
output.
ii. Contains feedback
c. Control System
i. A device or set of devices to manage, command, direct or regulate the behavior of other devices
or systems.
15. List 5 types of sensors and describe their function.
a. NTC resistor - A negative temperature coefficient, also known as a thermistor, is a sensitive resistor
b.
c.
d.
e.
f.
whose primary function is to exhibit a change in electric resistance with a change in temperature. Analog
Potentiometer - A switch that can provide variable motion control. It can vary the resistance within the
switch, which affects both the current and voltage flowing out of the switch. Analog
Reed switch - An electromagnetically operated switching device. Digital
Mini Switch - A device for making, breaking, or changing the connections in an electrical circuit. Digital
Phototransistor – A device used to detect the presence of light. Digital
Photoresistor – A device used to detect the amount of light present. Analog
16. Differentiate between analog and digital systems by describing a sample for each of them.
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a. Digital - A system of discrete states: high or low, on or off, 1 or 0. Mini switch, Reed switch,
Phototransistor
b. Analog - A signal having the characteristic of being continuous and changing smoothly over a given
range, rather than switching suddenly between certain levels. Potentiometer, Photoresistor, NTC resistor
17. Define the following fluid power systems by determining the source of their mechanical advantage:
a. Pneumatic
i. The use of gas flowing under pressure to transmit power from one location to another.
b. Hydraulic
i. The use of a liquid flowing under pressure to transmit power from one location to another.
18.
Complete the following table on laws and concepts of fluid transfer.
Law/Principle:
Pascal’s Law
Bernoulli’s Principle
Boyle’s Law
Gay-Lussac’s Law
Charles’ Law
Description
Pressure exerted by a confined fluid acts undiminished
equally in all directions
An increase in velocity results in a decrease in pressure.
Likewise, a decrease in velocity results in an increase in
pressure.
The volume of a gas at constant temperature varies
inversely with the pressure exerted on it.
Formula
Force = pressureXarea
Absolute pressure of a gas increases or decreases as the
temperature increases or decreases, provided the amount
of gas and the volume remain constant.
Volume of gas increases or decreases as the temperature
increases or decreases, provided the amount of gas and
pressure remain constant
p1 (V1) = p2 (V2)
p1
T1

p2
T2
V1 V2

T1 T2
19. List and describe the function of the 4 basic fluid power components.
a. Reservoir / Receiver - Stores fluid
b. Fluid Conductors - Pipe, tube, or hose that allows for flow between components
c. Pump / Compressor - Converts mechanical power to fluid power
d. Valve - Controls direction and amount of flow
e. Actuators - Converts fluid power to mechanical power
20. List and describe the advantages and disadvantages for the use of: water, gas and oil on fluid systems.
a. Water and Oil
i.
ii.
iii.
iv.
v.
vi.
vii.
viii.
b. Gas
i.
ii.
iii.
iv.
v.
vi.
Use a relatively incompressible liquid
Have a slower, smoother motion
Are generally more precise
Lubricate naturally
Are not as clean as pneumatics when leakage occurs
Often operate at pressures of 500 - 5000 psi
Generally produce more power
Water is cleaner than oil, but also is more compressible.
Possess a quicker, jumpier motion
Are not as precise
Require a lubricant
Are generally cleaner
Often operate at pressures around 100 psi
Generally produce less power
21. Describe the relationship between volume, pressure, and temperature if…:
a. temperature is constant
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i. The volume of a gas at constant temperature varies inversely with the pressure exerted on it.
b. initial volume is smaller than the final volume
i. Volume of gas increases or decreases as the temperature increases or decreases, provided the
amount of gas and pressure remain constant.
c. pressure is constant
i. Volume of gas increases or decreases as the temperature increases or decreases, provided the
amount of gas and pressure remain constant.
22. Define and list three samples for the following process:
a. Subtractive
i. Processes that remove material to change the size, shape, or surface of a part. There are two
groups of separating processes: machining and shearing. Ex: milling, drilling, turning.
b. Additive
i. The process of creating an object by adding small pieces or layers together to make a final
product. Ex: welding, adhesive bonding, soldering
c. Forming
i. A process that changes the size and shape of a material by a combination of force and a shaped
form. Ex: Rolling, forging, extrusion.
23. Provide a sample and description of the following:
a. Thermosetting
i. Formed into a desired shape by applying heat and pressure and being cooled, may be reheated
and remolded
b. Thermoplastics
i. Formed into a desired shape by applying heat and pressure and being cooled, may not be
reheated and remolded
c. Vulcanization
i. Chemical process that forms strong bonds between adjacent polymers to produce a tough rubber
24. Describe and differentiate between the following terms:
a. Toughness and hardness
i. Toughness – work per unit volume required to fracture a material, the ability of a material to
absorb energy without fracturing
ii. Hardness – a measure of how resistant a type of mater is to shape change
b. Brittle and fragile
i. Brittle – material failure with little or no ductility
ii. Fragile – a material that is easily broken or destroyed
c. Malleable and ductile
i. Malleable – capable of being shaped
ii. Ductile – amount of plasticity before fracture, the greater the ductility the more a material can be
deformed
25. Define the following terms:
a. Modulus of Elasticity
i. The ratio of the increment of some stress to some strain, the ability of a material to resist
stretching
b. Plastic Region
i. Unrecoverable elongation will not return to original shape
c. Elastic Region
i. Recoverable elongation, will return to original shape
d. Modulus of toughness
i. The measure of a materials ability to plastically deform without breaking
26. Calculate the stress and strain for a 0.5in diameter rod with a 100 ft length that has been elongated 1 in. from an
axial force of 60 lbs.
a. Stress = force/area
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stress = 60 lbs/(
x.252 in2)=305.58 psi
Page 5
b. Strain = elongation/length
strain = 1 in/1200 in
strain = 0.00083
27. Describe the following terms:
a. Static equilibrium
b.
c.
d.
e.
f.
g.
i. a condition where there are no net external forces acting upon a body, remains at rest or at a
constant velocity
Statically determinate
i. a structure that can be mathematically solved
Statically indeterminate
i. a structure that is over constrained so that there are more unknown supports than equations
Free body diagram
i. A diagram used to isolate a body from its environment showing all external forces acting on it
Moment of inertia
i. A property of a cross section that is concerned with a surface area and how the area is distributed
about a centroidal axis
Moment
i. The turning effect of a force about a point equal to the magnitude of the force times the
perpendicular distance from the force to the line of action
Centroid
i. The geometric center of an area
28. Study the truss system shown in Figure 1. How many reaction forces would replace the roller joint (C) if a free body
diagram of the truss system was drawn?
1 reaction force at point C.
29. For the problem above, calculate the force applied in the AC and BC trusses.
B
500 N
AC = 500 N in tension
BC = 707.1 N in compression
AB = 500 N in tension
707.1 N
500 N 500 N
45
500 N
500 N
500 N
45
A
500 N
500N
707.1 N
500N
C
500 N
500 N
500N
a. Cos 35 = adj/hyp
Hyp cos 35 = adj
36.99 ft/sec/sec cos 35 = 30.30 ft/sec
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b. X= Vi2 sin 2(35)/32.15 ft/sec/sec
X = 36.99 ft/sec(sin 2(35)/32.15 ft/sec/sec
X = 39.99 ft
c. Sin 35 = opp/hyp
Hyp cos 35 = opp
36.99 ft/sec/sec sin 35 = 21.21 ft/sec
c. What was the motorcyclist’s initial vertical velocity?
( Accuracy = 0)
30. The image to the right represents a:
a. normal distribution curve
b. Capacitor being charged
c. Elongation of an object
d. Deformation of an object under stress
31. Calculate the amount of effort force a man has to exert on the pulling rope from a pulley system with a
configuration similar to the one in the next figure. (show formulas used and units)
MA=FR/FE
60 lbs/3 = 20 lbs
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32. Calculate how much voltage is on a battery connected to the following circuit if the motor draws 0.25 amps and
provides 36 ohms of resistance as shown in the figure.
V=IR
V=0.25A(36ohms)
V=9V
33. Complete the following 5 sentences:
a. Temperature, energy and time are all examples of ___Scalar____ quantities.
b. Static equilibrium occurs in a truss system when the sum of the _moments_____________ is equal to
zero.
c. A part that is stressed well beyond its yield point will have __plastic________ deformation after the stress
is removed.
d. The process of loading a material to the point of failure for the purpose of collecting data on that
material’s physical properties is known as ___destructive testing_____________.
e. A free-falling object will experience a constant increase in speed per unit time. This is referred to as
__acceleration___ due to gravity.
34. From the following graph, identify the major points labeled A-D and complete the table recording the Force and
Displacement at each particular point:
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B
C
D
A
Point
Name of Point
Force (lbs)
Displacement (in)
A
Proportional stress limit
660
0.033
B
Yield point stress
685
0.037
C
Ultimate stress
717
0.068
D
Point of failure/breaking point
550
0.114
35. Use the same graph to calculate the following values given the sample
was originally 3 inches long and had a diameter of .15 inches :
(show all equations used).
a. Tensile/ Ultimate Stress:
i. Stress = 717 lbs/ x.0752)in2=40573.9 psi
b. Yield Stress:
i. Stress = 685 lbs/ x.0752)in2=38763.07 psi
c. Rupture Stress:
i. Stress = 550 lbs/ x.0752)in2=31123.63 psi
d. Total Strain at Rupture:
i. Strain = 0.114 in/3 in = 0.038
e. Modulus of Elasticity:
i. E =((660-25)3)/((.033-.01)( x.0752))=4,686,997.74 psi
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