NASA-Systems Engineering

# The abridged set given here is taken from that

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Unformatted text preview: difference and electromotive force) is the difference of electric potential between two points of a conductor carrying a constant current of one ampere, when the power dissipated between these points is equal to one watt. watt (W = J/s) The watt is the power that represents a rate of energy transfer of one joule per second. weber (Wb = V.s) The weber is the magnetic flux that, linking a circuit of one turn, produces in it an electromotive force of one volt as it is reduced to zero at a uniform rate in one second. C.2.5 Units in Use with SI Time The SI unit of time is the second. This unit is preferred and should be used if practical, particularly when technical calculations are involved. In cases where time relates to life customs or calendar cycles, the minute, hour, day and other calendar units may be necessary. For example, vehicle speed will normally be expressed in kilometers per hour. minute (min) 1 min = 60 s hour (h) 1 h = 60 min = 3600 sec day (d) 1 d = 24 h = 86 400 sec week, month, etc. Plane angle The SI unit for plane angle is the radian. Use of the degree and its decimal submultiples is permissible when the radian is not a convenient unit. Use of the minute and second is discouraged except for special fields such as astronomy and cartography. Volume The SI unit of volume is the cubic meter. This unit, or one of the regularly formed multiples such as the cubic centimeter, is preferred. The special name liter has been approved for the cubic decimeter, but use of this unit is restricted to volumetric capacity, dry measure, and measure of fluids (both liquids and gases). No prefix other than milli- or micro- should be used with liter. Mass The SI unit of mass is the kilogram. This unit, or one of the multiples formed by attaching an SI prefix to gram (g), is preferred for all applications. The megagram (Mg) is the appropriate unit for measuring large masses such as have been expressed in tons. However, the name ton has been given to several large mass units that are widely used in commerce and techn...
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## This document was uploaded on 02/26/2014 for the course E 515 at University of Louisiana at Lafayette.

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