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page 11

2.4 CALCULATIONS IN ENGINEERING

2.4.1 Units

we will use both SI Units and Imperial units,

Typical SI (System International) units are, m - meter (or mm, cm, km)

s - second (or min, hr, day, yr) kg - kilogram (or g, tonnes)

N- Newton (kg m/s2)

Typical Imperial Units are,

lb - pounds (or tons, oz.) in - inches (or ft, yd, mile) s - second

slug - mass (note: this is a proper unit of mass although we commonly use pounds)

These units can be combined to describe any numbers we have.

Note: the reader is expected to be aware of the basic rules of numbers and units.

see the section on units and watch some of the sample calculations for examples of proper application.

2.4.2 Significant Figures

• significant figures should be considered. One example of the effect of ignoring significant figures is given,

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