Physics Chapter 1 Topics

Overview:

Section 1: What Is Physics?
Scientific Method
Controlled Experiment and Variable

Section 2: Measurements in Experiments
SI (Le Système International d’Unités)
Accuracy and Precision
Measurement of Parallax
Significant Figures
Rules for Determining Significant Zeros
Rules for Rounding Numbers

Section 3: The Language of Physics
Shapes of Graphs and Mathematical Relationships
Evaluating Physics Expressions
Abbreviations for Variables and Units

Details
:
Section 1: What Is Physics?

Scientific Method

Section 2: Measurements in Experiments
SI (Système International or Le Système International d’Unités)

The unit of measurement for any physical quantity is derived from a combination of the seven base units. These base units are:

1. metre (m) -- length
2. kilogram (kg) -- mass
3. second (s) -- time
4. ampere (A) -- amount of electric current
5. kelvin (K) -- temperature
6. candela (cd) -- brightness (of light)
7. mole (mol) -- amount of (chemical) substance

Measurement

Accuracy and Precision

Problems with measurements
Measurement of Parallax
Parallax refers to an apparent shift in the position of an object when the object is viewed from different locations.

Consider a camera

Significant Figures
Significant figures are all the digits of a measurement known with certainty plus one final digit, which is somewhat uncertain or is estimated.
For example, if you used a ruler to measure a nail, you might find that the length of the nail was halfway between 6.3 and 6.4 cm. The ones and the tenths place are certain. The hundredths place is estimated and is the smallest significant figure you can find using a ruler. You write down the value as 6.35 cm.
Rules for Determining Significant Zeros

Five Rules for Determining the number of Significant Figures in a Measurement  

RULES

Rule 1. All nonzero integers are significant.
eg - 456 cm
456 cm
has 3 significant figures

Rule 2. All zeros to the left of the first nonzero digit are not significant since they are used to locate the decimal point.
eg - 0.00567 kg
0.00567 kg
has 3 significant figures

Rule 3. All zeros between nonzero digits are significant.
eg 1 - 207.08 cm
207.08 cm
has 5 significant figures

eg 2 - 0.0401 L
0.0401 L
has 3 significant figures

Rule 4. All zeros at the end of a number that has a decimal point are significant.
eg 1 - 34.070 mg

34.070 mg
has 5 significant figures

eg 2 - 0.0670 g
0.0670 g
has 3 significant figures

eg 3 - 400. mm
400. mm
has 3 significant figures

Rule 5. Zeros at the end of a whole number that has no decimal point is confusing since they may or may not be significant.
eg - 300 L
??????? The measurement, "300 L", as written is confusing.

Rules for Rounding Numbers
Section 3: The Language of Physics
Shapes of Graphs and Mathematical Relationships
Evaluating Physics Expressions
Abbreviations for Variables and Units

Section 3: The Language of Physics
Shapes of Graphs and Mathematical Relationships
The shape of a graph can be a clue to the mathematical expression that describes the relationship between the two variables.

Evaluating Physics Expressions
The term dimension is used to describe the kind of quantity that is being measured.
Length, mass, and time are examples of dimensions.
Use dimensional analysis and order-of-magnitude estimates to check your work.

Abbreviations for Variables and Units
Variables are typically represented in boldface or italicized type: v, t, F
A delta symbol ∆ preceding a variable is used to indicate the change over time in that quantity: ∆v
The units that accompany a value are expressed in regular type, as in these examples: s, kg

Links

Five Rules Significant Figures
http://nobel.scas.bcit.ca/chem0010/unit1/1.6_sigFig_3.htm


Rules for Rounding Off with problems:
http://dbhs.wvusd.k12.ca.us/webdocs/SigFigs/Rounding.html

Rounding Off Answers:
http://dbhs.wvusd.k12.ca.us/webdocs/SigFigs/Rounding-Ans.html

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