Engineering Problem Solving

1
Engineering Problem Solving Presentation

• ENGR 1020
• Chapter 3

2
Chapter Goals

• Fundamental Dimensions
• Engineering Analysis
• Communicating with a non-engineering World

3
Engineering Dimensions

• Anciently
• Length
• Mass
• Temperature
• Time
• Modern (Anciently )
• Electric current
• Amount of substance
• Luminous intensity

4
LSystem Internationale

• LRevolution (1799)
• Meter (Length) m
• the meter one ten-millionth of the length of the
  meridian through Paris from pole to the equator.
• wavelength of krypton-86 radiation
• length of the path traveled by light in vacuum
  during a time interval of 1/299 792 458 of a
  second
• Kilogram (Mass) kg
• a kilogram was the mass of a cubic decimeter of
  water
• the mass of the international prototype of the
  kilogram

5
LSystem Internationale

• Second (Time) 1832 s
• originally as the fraction 1/86,400 of the mean
  solar day
• The second is the duration of 9,192,631,770
  periods of the radiation corresponding to the
  transition between the two hyperfine levels of
  the ground state of the cesium 133 atom
• Ampere (Current) 1893 A
• The ampere is that constant current which, if
  maintained in two straight parallel conductors of
  infinite length, of negligible circular cross
  section, and placed 1 meter apart in vacuum,
  would produce between these conductors a force
  equal to 2 x 10-7 newton per meter of length

6
LSystem Internationale

• Kelvin (Temp) 1954 K
• originally Fahrenheit, Celsius
• the fraction 1/273.16 of the thermodynamic
  temperature of the triple point of water
• Mole (Amount) 1967 mol
• amount of substance of a system which contains as
  many elementary entities as there are atoms in
  0.012 kilogram of carbon 12

7
LSystem Internationale

• Candela (Intensity) 1967 cd
• In 1909 the United States of America, France, and
  Great Britain decided to adopt the international
  candle represented by carbon filament lamps
• the luminous intensity, in a given direction, of
  a source that emits monochromatic radiation of
  frequency 540 x 1012 hertz and that has a radiant
  intensity in that direction of 1/683 watt per
  steradian

8
Multiples and Prefixes

• How many miles in a yotta meters???
• .62137 zetta miles
• Commonly used prefixes
• Tera 1012
• Giga 109
• Mega 106
• Kilo 103
• Centi 10-2
• Milli 10-3
• Micro 10-6
• Nano 10-9
• pico 10-12

9
Derived Units

• MLT
• Density M/L3
• Force ML/T2
• Energy ML2/T2
• Power ML2/T3
• Pressure M/L/T2
• Velocity L/T
• Acceleration L/T2

10
Unit Conversion

• Convert
• Your height
• Weight
• Age
• Speed limit on I-15
• To SI units
• A pound is a pound the world around

11
Converting SI English

• Some common conversions you should know
• 2.54 cm per inch
• 3.28 feet per meter
• 3.78 liters per gal
• 1.05 quarts per liter
• 60 cu. in per liter
• 1.6 km per mile
• 2.2 pounds per kg

Helpful hints use the conversion factors like
fractions
12
Homogeneity of Dimensions

• Dimensions on the Left side of an equation are
  equal to the dimensions on the Right.
• Dimensions in the numerator cancel like
  dimensions in the denominator.
• ALWAYS report result dimensions!!!
• ALWAYS report result dimensions!!!
• ALWAYS report result dimensions!!!