Fundamental Dimensions

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Fundamental Dimensions
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Why do we need fundamental or base dimensions?

• To communicate effectively
• To agree on standards

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Why do we need Units

• To keep numbers manageable
• I am 19 years old
• I am 170,000 hours old
• I am 612,000,000 seconds old
• I am 228 moons old!

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The seven base dimensions

• Length
• Mass
• Time
• Electric Current
• Temperature
• Amount of Substance
• Luminous Intensity

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SI (International System of units)

• Length Meter m
• Mass kilogram kg
• Time second S
• E Cur. Ampere A
• Temp. Kelvin K
• Am. Sub Mole mol
• Lumin candela cd

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Formal Definitions

• Meter Length of path of light traveled in a
  vacuum during 1/299,792,458 of a second
• Kilogram the mass of an international prototype
• Second 9,192,631,770 periods of the transition
  state of Cesium 133

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Formal Definitions Cont.

• Ampere the current which would produce a force
  of 2x10-7 newton between two parallel wires 1
  meter apart.
• Kelvin a unit of thermodynamic temperature,
  1/273.16 of the triple point of water and
  absolute zero.
• Mole the number of elementary entities as found
  in 0.012 kg of Carbon 12

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Formal Definitions Cont.

• Candela the luminous intensity of a source tht
  emits radiation of frequency 540 x 1012 hertz and
  has a radiant intensity in that direction of
  1/683 watt per steradian.

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Examples of SI units

• Camera Film 35 mm
• Dose (medication) 10 mg, 500 mg
• Sports swimming and running the 100 m, 400m,
• Cars Engine - 2.2 liter, 4.7 liter
• Electrical Consumption kW/hr

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Examples of SI units

• Radio Stations
• 88-108 Mhz (FM)
• 0.54-1.6 Mhz (AM)
• Police Fire
• 153-159 Mhz
• GPS 1575 Mhz
• Relationship between wavelength and frequency
• l v/f wave velocity/freq
• where v 3 x 108 m/s

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Example Cell Phone

• Some transmit on 1500 mhz
• (Note 1 mhz 106 hz)
• l 3 x 108 m/s 3 x 108 m/s
• 1500 mhz 1.5 x 109 cyl/s
• l 0.2 Meters or 20 cm

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Engineering Components and Systems

• What is an engineering system
• What is an engineering subsystem
• What is an engineering component
• Examples jacket, car, plane

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Solution of Engineering problems

• What is the problem?
• Can I simplify the problem?
• Solution or Analysis
• Verification of Results

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Radio Frequency Identification (RFID)

• Tracking tags attached to materials,
  productshumans?
• RFID tags have 128 bit address
• Sufficient for 1038 items
• Expect 1012 RFID tags created
• Currently 1.00 each
• Future 0.01 _at_ 1012 units (10 billion market)
• WalMart is tagging all merchandise
• Eli Lilly expects to tag every pill bottle!

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System Ranges
From www.node-net.com
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Example Wireless Camera for Rocket Project

• Remote camera transmits at 2.4 ghz
• l 3 x 108 m/s 3 x 108 m/s
• 2.4 ghz 2.4 x 109 cyl/s
• l 13 cm
• Receiver antenna is 6.5 cm long its a half
  wavelength antenna.
• Transmission antenna is 1.3 cm long.

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HW 3

• 1) Conversions Show all appropriate units that
  go with calculations
• An engineering student who is 5 feet 8 inches
  tall and weights 165 pounds is boating in a lake
  at 7 miles per hour over a distance of 20 miles.
  The outside air temperature is 77oF and the water
  temperature is 45oF with respective densities of
  0.0735 pounds per cubic foot and 8.3 pounds per
  gallon.
• Convert all values given in this example from US
  customary units to SI units.
• Refer to web sites such as onlineconversions.com
  for assistance.
• (Please do not use ragged edge paper.)
• Due Monday July 11th

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HW 4

• Research a device that emits EMF energy and
  compute the wavelength of the emissions. If the
  device contains an antenna, determine what
  division the antenna represents ie full wave,
  half wave, quarter wave
• Due Tuesday July 12th