01physicalquantities-150326053307-conversion-gate01[1].pptx

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1. Unit 1 Phys i cs IAL Physical Quantities

2. Outcomes Students will be able to understand: Physical Quantities International System of Units (SI) Basic and Derived Quantities Standards in SI Instruments for Measurement. Representation of Measurements. Prefixes and their uses 2

3. Physical Quantities A physical quantity is one that can be measured/observed and consists of a magnitude and unit. 70 k m /h  4.5 m  Quantity : Height(Length) Magnitude : 4.5 Unit : meter (m) Quantity : Speed Magnitude : 70 Unit : kilometer per hour Quantity : Temperature Magnitude : 33 Unit : celcius 3

4. More Examples of Physical Quantities 4 T ime A r ea Pressure Energy Weight Volume

5. Measurement of Physical Quantities Physics is all about the observation and measurement of nature / physical quantities. Types of Observations: Qualitative and Quantitative Example: The new iPhone 5s is expensive. Its price is R.O. 270 5 Example: Ali is a tall boy. His height is 6 feet. Example: The land area of Monaco is small and it is densely populated. It has an area of 1.98 km 2 with a population of 35,986

6. Standard for Measurements Every measurement must have a standard !!! Every Standard must have the following properties 6 Inv a riable + Accessible

7. The General Conference on Weights and Measures (CGMP) is responsible for the definition of the SI units. First Meeting : 1883 23 rd Meeting : 2010 Next Expected: 2015 International System of Units (SI) 7

8. Types of SI Units Basic Quantities are the building blocks but the Derived Quantities are made from the Basic. 8 Supplementary Quantities are not still decided- whether in Basic or Derived Basic Derived Supplementary

9. Basic SI Quantities and Units 9 Quantity SI Unit Symbol of Unit Length meter m Mass kilogram kg Time second s Electric Current ampere A Thermodynamic Temperature kelvin K Luminous Intensity candela cd Amount of Substance mole m ol Similar table : Table 1-15, P-10 (Giancoli)

10. Some Derived SI Quantities and Units Quantity SI Unit Symbol of Unit Speed meter per second m s -1 Force newton N m s -2 Acceleration meter per sec per sec Area square meter m 2 Pressure pascal Pa Volume cubic meter 10 m 3 Many More . . .

11. Examples of Derived SI Quantities and Units 11 Defining equation: area = length × width In terms of units: Units of area = m × m = m 2 Defining equation: volume = length × width ×height In terms of units: Units of volume = m×m×m = m 3 Defining equation: density = mass ÷ volume In terms of units: Units of density = kg/m 3 =kg m −3

12. Work out the derived quantities for: Defining equation: speed = distance / time In terms of units: Units of speed = Defining equation: pressure = force / area In terms of units: Units of pressure = Defining equation: force = mass × acceleration In terms of units: Units of force = Practice: Derived SI Quantities 12

13. Supplementary SI Quantities and Units 13 Quantity SI Unit Symbol of Unit Plane Angle radian rad Spherical Angle steradian str

14. Prefix e s To represent very small or very large numbers the prefixes can be used. Name Symbol Number Powers of 10 tera T 1 000 000 000 000 10 12 giga G 1 000 000 000 10 9 mega M 1 000 000 10 6 kilo k 1 000 10 3 hecto h 1 00 10 2 deca da 1 10 1 1 10 deci d 0.1 10 -1 centi c 0.01 10 -2 milli m 0.001 10 -3 micro µ 0.000 001 10 -6 nano n 0.000 000 001 10 -9 pico p 0.000 000 000 001 10 -12 14

15. Practice Questions 15 Find at least 5 derived quantities and write the SI units Write the following quantities using suitable prefixes. a. 5 000000 J b. 5000 g c. 0.009 s 3. How many meters in a kilometer? 4. How many second in a microsecond?