Introduction Which of the following professionals (專業人仕) need knowledge (知識) of physics? Medical Doctor (醫生) Accountant (會計師) Civil Engineer (土木工程師) Lawyer (律師) Car Designer (汽車設計師) Salesman / Saleslady (售貨員) Physicist (物理學家) Clerk (文員) Chemist (化驗師) Waiter / Waitress (待應)  

Introduction Civil Engineer (土木工程師) Car Designer (汽車設計師) Which of the following professionals (專業人仕) need knowledge (知識) of physics? Medical Doctor (醫生) Civil Engineer (土木工程師) Car Designer (汽車設計師) Physicist (物理學家) Chemist (化驗師) 2

How many aspects of Physics do you see in this photograph?

What is PHYSICS? * Branch (分支) of science, … * Study of atoms (原子), molecules (分子), … to earth (地球), sun (太陽), … * Study of force (力) , energy (能量) , … * Study the laws of nature (自然定律), … * Experiments (實驗), …

Physical Quantities (物理量) Distance (距離) Time (時間) Mass (質量) Temperature (溫度) Volume (體積) Density (密度) ......

Unit (單位) Physical Quantity (物理量) Unit (單位) Symbol (符號) Length (長度) metre (米) m Time (時間) second (秒) s Mass (質量) kilogram (千克) kg

Which of the following is the correct SI unit of time? Class Exercise 1.1 Which of the following is the correct SI unit of time? year month minute D. second 7

Which of the following is the correct SI unit of time? Class Exercise 1.1 Which of the following is the correct SI unit of time? year month minute D. second 8

Class Exercise 1.2 Which of the following symbols represents the correct SI unit of mass? g kg Kg KG 9

Class Exercise 1.2 Which of the following symbols represents the correct SI unit of mass? g kg Kg KG 10

Sub-unit giga G 109 mega M 106 kilo k 103 centi c 10-2 milli m 10-3 Prefix (字首) Symbol (符號) Index Multiple giga G 109 1,000,000,000 mega M 106 1,000,000 kilo k 103 1,000 centi c 10-2 1/100 milli m 10-3 1/1000 micro μ 10-6 1/1,000,000 nano n 10-9 1/1,000,000,000

Convert the following quantities. 20 km = ______________ m Class Exercise 1.3 Convert the following quantities. 20 km = ______________ m 29 ns = ______________ s 0.27 g = ______________ kg 612 nm = ______________ m 0. 000 25 Ms = ______________ s 34.5 g = ______________ g 12

Convert the following quantities. 20 km = ______________ m Class Exercise 1.3 Convert the following quantities. 20 km = ______________ m 29 ns = ______________ s 0.27 g = ______________ kg 612 nm = ______________ m 0. 000 25 Ms = ______________ s 34.5 g = ______________ g 13

Significant Figures (有效數字) All measured (測量) quantities have unavoidable (不可避免) error (誤差). The more number of significant figures, the more accurate (準確) is the measurement. All non-zero figure (1, 2,…9) is significant. “Zero” may be or may not be significant.

No. of Significant Figures Examples: Value No. of Significant Figures 5 1 51 0.67 0.0021 2 123 32.1 4.56 0.000803 3 2468 1.002 4

(a) 567 (b) 2.68 (c) 0.000 012 3 (d) 100.123 (e) 21 Class Exercise 1.4 Which of the following quantities are expressed in 3 significant figures? (a) 567 (b) 2.68 (c) 0.000 012 3 (d) 100.123 (e) 21

(a) 567 (b) 2.68 (c) 0.000 012 3 Class Exercise 1.4 (d) 100.123 (e) 21 Which of the following quantities are expressed in 3 significant figures? (a) 567 (b) 2.68 (c) 0.000 012 3 (d) 100.123 (e) 21 17

(a) 2 (b) 1234 (c) 0.0013075 (d) 34 (e) 30 (f) 400 Class Exercise 1.5 What is the number of significant figures of the following quantities? (a) 2 (b) 1234 (c) 0.0013075 (d) 34 (e) 30 (f) 400

(a) 2 (1) (b) 1234 (4) (c) 0.0013075 (5) (d) 34 (2) (e) 30 (2) or (1) Class Exercise 1.5 What is the number of significant figures of the following quantities? (a) 2 (1) (b) 1234 (4) (c) 0.0013075 (5) (d) 34 (2) (e) 30 (2) or (1) (f) 400 (3) or (2) or (1) 19

Class Exercise 1.6 Write the following numbers in 3 significant figures. (a) 532.0243 (b) 2.2648986966 (c) 4.56789 (d) 0.0012345698 20

Class Exercise 1.6 Write the following numbers in 3 significant figures. (a) 532.0243 532 (b) 2.2648986966 2.26 (c) 4.56789 4.57 (d) 0.0012345698 0.00123

Remember to bring a CALCULATOR (計算機) and a RULER (直尺) with you in the next lesson. 22