Engineering Design
What are the 8 steps of the engineering design process?
identify the problem, research the problem, develop possible solutions, select the best possible solution(s), construct prototypes and/or models, test and evaluate, communicate the solutions, and redesign
What does the r-value of a material tell us about that material?
Its resistance to heat flow
What is the difference between an open system and a closed system?
Open - interacts with the environment. Closed - does not interact with the environment.
What kind of current (AC or DC) comes out of a wall outlet?
Alternating Current
Heat is lost from a building by conduction. Which material would be best to help prevent heat loss from a 4.5 in. thick wall? One with a high r-value or one with a low r-value.
high r-value
A house is 40ft long. If the scale used is 2" = 1' how many inches long should the house be drawn?
80 inches
What is the difference between zoning laws and building codes?
zoning laws - where things can be built building codes - how things can be built
What kind of fluid can be used in a hydraulic system and what kind of fluid can be used in a pneumatic system?
Hydraulic - liquids Pneumatics - gases
What is the purpose of a fuse or a circuit breaker?
to protect electrical circuits from overloads or short-circuits.
A house is being built in Maine. How can the design maximize both passive solar heating and the amount of natural light inside the house?
a large number of south-facing windows
How many views are usually necessary in order to describe an object using an orthographic projection?
2 or 3
Explain Bernoulli's principle.
As velocity increases pressure decreases, and as velocity decreases pressure increases.
In a hydraulic system, an input piston has an area of 10 sq. in. and has a force of 20 lbs placed on it. The output piston has an area of 50 sq. in. What is the output force?
100 lbs.
A circuit has 36 volts running through a resistor with 6 ohms of resistance. What is the current? (Include units)
6 Amps
Where is the best place to put a thermostat in a room?
-By the window
-By the door
-Next to the heater
-Away from windows or heater
-On exterior wall
-Away from windows or heater
A scale drawing of a rectangular storage tank has a scale of 1cm=0.5m. The dimensions of the tank on the drawing are 24cm x 32cm x 20cm. What are the dimensions of the actual storage tank?
12m x 16m x10m
There are 3 desks and 7 chairs in a room. Each chair weighs 5 pounds and each desk weighs 25 pounds. What is the live load in the room?
110 lbs
Explain how increasing the size of a pipe effects the velocity of fluids.
increasing pipe size - slower liquid
Identify the three different instruments used to measure voltage, current, and resistance.
voltage - voltmeter
current - ammeter
resistance - ohmmeter
Provide one example of a non-renewable energy source and one example of a renewable energy source.
Non-renewable - any petroleum based source, uranium
Renewable - solar, wind, geothermal
Advances in military technologies have often led to the development of everyday applications. Early radar systems operators noticed that objects near the radar were often heated when the radar was in use. This observation led to the development of what everyday applications?
microwave ovens
Explain tension, compression, shear, and torsion.
tension - pulling apart compression - pushing together shear - pushing in opposite directions torsion - twisting
A pipe has a 45º elbow and a 90º elbow. Where is resistance greatest?
90º elbow
How does the temperature of a wire affect the resistance in the wire?
Higher temperature = higher resistance lower temperature = lower resistance
Describe conduction, convection, and radiation?
conduction - heat transfer via direct contact convection - heat transfer via gases or liquids radiation - heat transfer via electromagnetic waves