CHAPTER 1 INTRODUCTION
The basic laws of physics involve such physical quantities as force, velocity, volume, and acceleration, all of which can be described in terms of more fundamental quantities. In mechanics, it is conventional to use the quantities of length (L), mass (M), and time (T); all other physical quantities can be constructed from these three.
Standards of Length, Mass, and Time
Length
In 1799 the legal standard of length in France became the meter, defined as one ten-millionth of the distance from the equator to the North Pole. Until 1960, the official length of the meter was the distance between two lines on a specific bar of platinum-iridium alloy stored under controlled conditions. This standard was abandoned for several
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The following are the rules to find the number of significant figures: All non-zero digits are considered significant figures. Examples: 123 456 = has six significant figure 219 = has three significant figure Zeros used to position the decimal point (leading zeros) are not considered significant figures. Examples: 0.0032 = has two significant figure 0.07 = has one significant figure Zeros in between two non-zero digits are considered significant figures. Examples: 303 804 = has six significant figures 0.030 9 = has three significant figures All zeros to the right of the last non-zero digit (trailing zeros) in a number having no decimal point are not significant. Examples: 12 000 = has 2 significant figures 3 000 = has 1 significant figure Use scientific notation to indicate the number of significant figures to remove ambiguity. Examples: 3.302 x 102 = has 4 significant figures 2.00 x 10-4 = has 4 significant figures When multiplying or dividing, the number of significant figures in the final answer is the same as the number of significant figures in the quantity having the lowest number of significant