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Physics Chapter 1 Summary- Measurement by
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# Physics Chapter 1 Summary- Measurement

## Physical Quantities

### Derived quantity

A product of base quanitities

E.g.,, area= length x width, volume= length x width x height, force= mass x accelaration

## SI units- International system of units

### Includes Length, Mass, Time, etc.

Important Units, Base Quantities/Name/Symbol, Length/Meter/m, Mass/Kilogram/kg, Time/Second/s, Electric Current/Ampere/A, Derived Quantities/Equation/Symbol/Special name (if any), Area/l x w/m (2), Volume/l x w x h/m (3), Force/m x A/.../Newton (N)

## Prefixes

nano/n/10^-9

mirco/µ/10^6

milli/m/10^-3

centi/c/10^-2

deci/d/10^-1

kilo/k/10^3

mega/M/10^6

giga/G/10^9

tera/T/10^12

### They increase/decrease by thousands, most of the time

E.g., From kilo(10^3) to mega(10^6)

## Measurement of Length

### Accurate measurement

No measurement is perfectly accurate

Three types of Errors, Random, They are inconstant errors, e.g., time of one oscillation, Systematic, A consistant error in measuring, e.g., measuring without adding/deducting the zero error., Parallex, The eye is not aligned with the measuring tool OR the object is not aligned with the scale

Read the measurement (length) when..., Your eyes are perpendicular to the scale, The object is aligned properly with the ruler

### Types of Measurement tools (Please note that I own none of the videos)

Ruler, For short lengths (≥30)

Meter Rule, For lengths ≥1m

Measuring tape, For longer length (depends, usually ≥3m)

Vernier Caliper, For an accuracy of 0.01cm, Parts, Inner Jaws, Measure Inner Diameter, Outer Jaws, Measure Length, Main Scale, Mark it against the Vernier Scale (0.0cm), Vernier Scale, Measure the length (0.00cm), Depth Probe, Measure Depth, http://www.youtube.com/watch?v=hraBV0eFPZU&feature=related, Note: Some part names in the video are different from mine. Follow mine., How to use it, http://www.youtube.com/watch?v=kTLhmptHAPc&feature=related

Micrometer Screw Gauge, For an accuracy of 0.01mm, Parts, Anvil, The little tip at the end of the frame, Spindle, The spindle and the anvil clamp on the object that is being measured, Sleeve, The main scale is on the it, Thimble, The circular scale is on it, Ratchet, Prevents the spindle from over screwing, How to use it, http://www.youtube.com/watch?v=O8vMFFYNIfo&feature=related, Please note that the anvil is at the point where the spindle reaches the end, the little tip. The video marked the frame as the anvil, that is wrong.

## Measurement of Time

### Accurate Measurement

Don't measure races to the point of 0.01s, because the reaction time might lag

### Types of Measurement Tools

Watch, For long intervals of time, Most depend on quartz crystals for accurate timing, Battery, Quartz, Coiled Spring

Digital Stopwatch, Up to an accuracy of 0.01 seconds

Analogue Stopwatch, Up to an accuracy of 0.1 seconds

Pendulum Clock, For long intervals of time, The pendulum swings and the gravitational potential energy is converted into elastic potential energy., An oscillation is when a pendulum swings from one point and back, The time for a complete oscillation is called one period

## Measurement of Area, Volume and Mass

### Area

Regular, m^2 and cm^2 are normally used, To calculate this, use a formula, depending on the shape

Irregular, Place the object on a square grid and trace it. Count the number of more than half filled squares to be the area, To be more accurate, use a smaller grid

### Volume

Regular, m^3 and cm^3 are normally used, To calculate this, use a formula, depending on the solid

Irregular, Fill a measuring cylinder to a certain amount of water and lower the solid in. The increase of the water level is the volume

### Mass

kg and g are normally used

Measurement Tools, Beam Balance, Electronic Balance

## Temperature Measurement

### Thermometers

Alcohol, It is coloured to increase visibility, Range: -70ºC to 78ºC

Mercury, It is poisonous, Range: -38.83ºC to 356ºC