MATHEMATICS IN SCIENCE

Objectives

1. To give concrete examples on how mathematics play an important role in our everyday life

2. To solve problems involving the SI unit of measurement and Scientific Notations

3. To become familiar with the different tools used for measurement

• SI =Systeme International d’Unites. • based on the metric system of measurement

that was developed by France. • ideal because it is a decimal system. • Simple relations exist between units and

equivalents and they are expressed in multiples of 10.

• SI is consist of a set of units together with a set of prefixes.

SEVEN SI BASE UNITSQuantity Name Symbol

Mass kilogram kgTime second s

Length meter mElectrical current ampere A

Temperature kelvin KAmount of substance mole molLuminous intensity candela cd

TABLE OF PREFIXES USED IN SI UNITS

Prefix Abbreviation

Exponential expression

Decimal Expression

Mega M 106 1,000,000Kilo K 103 1,000

Hekto H 102 100Deka da 101 10Deci d 10-1 0.1Centi c 10-2 0.01Milli m 10-3 0.001

Micro μ 10-6 0.000001nano n 10-9 0.000000001

English system1 in = 2.54 cm 1 ft = 0.3 m1 yrd = 0.91 m1 mi = 1.61 km1 ml = 1cm3

1 liq quart = 0.95 L1 dry quart = 1.10 L1 gal = 3.80 L

1oz = 28.35 g1lbs = 0.45 kg

Conversion of units

• Conversion Factor must always be equal to 1• how many meters can be found in 5

kilometers?

5km x 103m = 5000m 1 1km

Significant FiguresTo avoid ambiguity in the number of significant figures, such number should be written in exponential notation

730 (3 significant figures) – 7.30X102

760 (2 significant figures) – 7.6X102

16,000 (3 significant figures) – 1.60x104

ROUNDING OFF RULES1. When the number dropped is less than 5, the preceding number remains unchanged. Thus, 1.874 rounded off to 1.87 and 0.056452 is rounded off to 0.05645.

2. When the number dropped is more than 5, 1 is added to the preceding number. Thus, 4.7438 is rounded off to 4.744 and 0.0526 is rounded off to 0.053.

3. When the number dropped is exactly 5, if the preceding number is even, it remains unchanged; if the preceding number is odd, 1 is added to it. Thus, 7.245 is rounded off to 7.24 and 13.7735 is rounded off to 13.774.

Rounding off for Addition and Subtraction

• The answers should be rounded off so as to contain the same number of decimal places as in the number with the least decimal places.

Rounding off for Multiplication and Division

• The answer should be rounded off as to contain only as many as significant figures as in the number with the least number of significant figures.