The Physics
Opus in profectus

British-American System of Units

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  1. Write something.
  2. Write something.
  3. Write something.
  4. Write something completely different.


  1. Read the following passage from the 18th century British philosopher and economist Adam Smith.

    In like manner there were natural measures of quantity, such as fathoms, cubits, inches, taken from the proportion of the human body, were once in use with every nation. But by a little observation, they found that one man's arm was longer or shorter than another's, and that one was not to be compared with the other, and therefore wise men who attended to these things would endeavour to fix upon some more accurate measure, that equal quantities might be of equal values. Their method became absolutely necessary when people came to deal in many commodities, and in great quantities of them.

    Adam Smith, 1763

    1. Why does Adam Smith think units are important in economics?
    2. Why are units are important in science?


  1. Calculate the number of kilometers in 20.0 miles (note: 1 mile = 5,280 ft, 1 ft = 12 in, 1 m = 39.34 in).
  2. The nanoacre is a unit invented by computer engineers as a joke. It is said that one nanoacre of an integrated circuit (a computer chip) costs about the same to develop as an acre of real estate. Determine the length of the side of a square with an area of one nanoacre in…
    1. inches
    2. millimeters