Dimension, Scientific Notation, And Significant Number

Dimension, scientific notation, and significant number

SMA-5-BKS-RSBI/Physics/10th/2009-2010/page3/Rini 3/08/09/week4

• Dimension is the symbol to show how a quantity is arranged from basic quantity • Dimension of Basic quantities: M, L, T, I, J, N and Ө • Dimension of Derivative quantities Steps: 1. Find the formula • 2. Find the units (basic quantity) • 3. Find the dimension • Example: Find the dimension of force • • the formula : F = m.a : = kg. m/s2 • the units : = M. L/T2 • the dimension

• Scientific notation is the way to express smaller and larger number. a x 10n • • with 1‹ a ‹ 10 and n is the integer 0.000036 = 3.6 x 10-5 • Example: 76800000= 7.68 x 107 •

Significant number is the number that gets from measurement. The rules 1. All figures (but zero) are significant number Example: 213.6 gram (4 significant number) 45.7 cm (3 significant number) 2. All zeros lie between non-zero figures are significant number Example: 201.06 m (5 significant number) 4.008 Kg (4 significant number)

3. All zeros number at the right hand side of nnonzero figure are significant number, unless there is a special explanation with underlined Example: 5280 cm (4 significant number) 5280 cm (3 significant number) 4. All zeros used to determine the position of the decimal point are not significant number Example: 0.0067 mm (2 significant number) 0.0308 gr (3 significant number)

The mathematical operation of significant numbers • • •

Addition and subtraction Example: 29 500 + 6 950 = 36 450 ≈ 36 500 530 – 287 = 243 ≈ 240

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Multiplication and division Example: 796 x 320 = 254 720 ≈ 255 000 5.63 x 0.8 = 4.504 ≈ 5 0.428 : 0.7 = 0.6114 ≈ 0.6

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Power and roots Example: 3.283 = 35.287552 ≈ 35.3 3.28 = 10995.116 ≈ 11 000 √196 = 14.0

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Exercise Task : Do the test in Student’s Worksbook at page 19 part III