Physical Quantities and Units http://thinkzone.wlonk.com/Units/PhysQuantities.htm

1. Mass

1.1. SI Unit- Kilogram (KG)

1.2. measured via Electronic Beam Balance/ Sliding Balance

1.3. Mass and Weight are NOT the Same!

2. Length

2.1. Metre- length of the path travelled by light in a vacuum during a time interval of 1/299792458 of a second.

2.2. Metre Rule

2.2.1. Accurate to 0.001 m ( 1 millimeter)

2.2.1.1. Max-1.000m

2.2.1.2. Min-0.001m

2.3. Venier Calipers

2.3.1. Accurate to +/- 0.01cm

2.3.1.1. Inside jaws to measure interiors diameters

2.3.1.2. Outside jaws to measure exterior diameters

2.3.1.3. Tail to measure depths

2.4. Micrometer Screw Gauge

2.4.1. Accurate to +/- 0.001 cm

3. Prefixes in units

3.1. To express numbers involving decimals

3.2. 1012 tera T 109 giga G 106 mega M 103 kilo k 102 hecto h 101 deka da Factor Name Symbol 10-1 deci d 10-2 centi c 10-3 milli m 10-6 micro µ 10-9 nano n 10-12 pico p 10-15 femto f

4. Physical Quantity /Base Unit/ Symbol Length / metre / m Mass / kilogram / kg Time / second / s Electric Current / ampere / A Temperature / kelvin / K Luminous intensity/ candela/ Cd Amt of Substance / mole/ mol

5. Time

5.1. Second- Defined as: 9.192.631,700 times the period of oscillation of radiation from the cesium atom

5.2. Digital Stopwatch used to measure short time intervals

5.2.1. Accurate to +/- 0.01 s

5.3. Analogue Stopwatch

5.3.1. Accurate to +/- 0.1 s

5.4. Human reaction error when using stopwatch 0.3 s incurred

5.5. Mechanical instruments: watches/ticker-tape timers

5.5.1. Use repetitive motion/vibrations

5.5.1.1. Known as- Oscillations

5.5.1.2. Time to complete 1 Oscillation= Period of oscillation