Transcript Chapter 1: The Physics Tool Kit

CHAPTER 1:
THE PHYSICS TOOL KIT
Sections 1.1 and 1.2
The Physics Tool Kit: Ch1, Sections 1 and 2
Objectives
 Explain the need for standardization of
measurement.
 Use the metric and English systems of
measurement.
Introduction
 The physics student must be able to:
 Analyze a problem
 Choose a correct concept formula
 Manipulate an equation
 This chapter gives the basic tools for a
physics student.




Math techniques
Significant digits
Accuracy and precision
Problem solving strategy
1.1 Standards of Measure
 Standard of measure – sets units of
measurement for length, weight, and other
quantities defined in a way that is useful to a
large number of people.
 Some interesting historical
measurement standards.
http://en.wikipedia.org/wiki/Pottle
 Chain – 100 links used for surveying = 66 ft
 Rod – 16 men lined up foot to foot; now
standardized to 16 1/2 feet
 Yard – tip of king’s nose to fingertips of
outstretched hand.
 Foot – rod divided by 16; was also common
to use length of one’s own foot.
 Inch – was the length of three barely
corns.
 US system, sometime called English system, of
measurements is a combination of Anglo-Saxon,
Roman, and French-Norman weights and
measures.
 In 1790’s, a decimal system based on the metric
system was developed in France
 Many nations began adopting as official measurement
system.
 By 1970, the US was the only non-metric industrialized
nation.
Lost in Space
http://www.cnn.com/TECH/space/9909/30/mars.metric/
 Many businesses, industry and government
agencies in the US have now converted
voluntarily to the metric system.
 In many industries, you – the student and worker
– will need to know and use both.
1.2 Introduction to the
Metric System
 SI System of measurement is based on metric
system
 Gabriel Mouton (1618-1694)
 System is based on factors of 10
 Units are made bigger or smaller by using SI prefixes
SI Base Units
Basic Unit
SI Abbreviation
Quantity Measured
meter
m
length
kilogram
kg
mass
second
s
time
ampere
A
electric current
Kelvin
K
temperature
candela
cd
light intensity
mole
mol
amount
SI Derived Units
Derived Unit
Abbreviation
Quantity Measured
liter
L of l
volume
cubic meter
m3
volume
square meter
m2
area
Newton
N
force
meter per second
m/s
speed
Joule
J
energy
watt
W
power
SI Prefixes
Multiple
Power of 10
Prefix
Prefix Symbol
1 000 000 000 000
1012
tera
T
1 000 000 000
109
giga
G
1 000 000
106
mega
M
1000
103
kilo
k
100
102
hecto
h
10
101
deka
da
1
100
(base)
-
0.1
10-1
deci
d
0.01
10-2
centi
c
0.001
10-3
milli
m
0.000 001
10-6
micro

0.000 000 001
10-9
nano

0.000 000 000 001
10-12
pico
p
Comparison of English and SI Units
System
Length
Time
Mass
Force & Weight
English
foot (ft)
second (s)
slug
pound (lb)
SI
meter (m)
second (s)
kilogram (kg) Newton (N)
Weight and Mass Conversions
1 lb = 16 ounces (oz)
1 kg weighs 9.80 N or 2.2 lb
1 lb = 4.45 N
1 slug weighs 32.2 lb
1 kg = 1000 g
1 slug = 14.59 kg