Notes
Outline
Technical Physics 2
Chapter 2
Measurement
What’s the answer?
Problem Solving  (5 steps)
1. Identify the question (problem)
2. List the important data
3. Write the formula or facts which relate the question with the known data
4. Substitute data into the formula
5. Calculate
Does it answer the question ?
Does the answer make sense ?
Is there a need for rounding ?
What do we measure?
Fundamental properties
mass (weight) kilogram
length meter
time second
temperature Kelvin
*electric charge (coulombs) and light intensity (candela) will be discussed later in this class
Derived quantities
density, velocity, force, etc...
Systems of measurement
Metric system vs English system
Metric (SI) International system
standardized
international
consistent base units
multiples of 10
English (US) system
non-standard
only US
no consistent base units
no consistent multiples
Using the Metric system
Base units
mass            gram(g)
length          meter (m)
liquid volume       liter (l)
time             second (s)
Prefixes for multiples of 10
T - - G - - M - -k h d (base) d c m - - m - - n - -p
move the decimal to convert
Moving the decimal
Converting measurements
Metric Metric
multiples of 10
move decimal
*area - move twice
*volume - move three times
English          Metric
conversion  factors
proportion method
unit cancellation method
Proportion method
Unit cancellation
Scientific notation
Used for expressing very large or very small values
standard form
base x 10exponent
base is between 1.0 and 9.999…
if exponent is positive the value is greater than 1
if exponent is negative the value is less than 1
convert to decimal by moving the decimal the number of places indicated by the exponent
Proper SI form
Used to write numbers with reasonable values
move the decimal to show a value in the range of  0.1 to 1000
include the metric prefix to indicate the number of decimal places moved
Rounding
Significant digits
The digits reported in a measured quantity
Indicate the precision of the measuring instrument
Calculations should not have more significant digits than the measurement with the least number of significant digits
*In this class we will use rounding to help make calculations understandable and useful. In some instances this will yield slightly different results.