Test 3 Flashcards
A_is the act of comparing and unknown quantity to a standard unit. Consists of a_and a_
Measurement, number, unit
An_is any artificial device made for the purpose of refining, extending, or substituting for the human senses when measuring
Instrument
A__system is any measuring system in which different sized units are related to each other by multiples of 10
Metric
Area
Square meter
m^2
Volume
Cubic meter
m^3
Mass density
Kilogram per cubic meter
kg/m^3
Metric ton
Mass
t
Atomic mass unit
Mass
u
A__is a fraction that contains both the original unit and it’s equivalent value in a new unit and is_to_
Conversion factor, equal, 1
What is the basic rule for using conversion factors
In a conversion factor ratio, the new unit is in the numerator and the old unit is in the denominator
A quantitive term that describes how close a measurement is to the actual or accepted value of the dimension being measured
Accuracy
What is the formula for percent error
(|o-A|/A)•100%
O= observed value
A= accepted value
If the percent error is_, then the measurement is considered to be accurate
Small
A quantitive evaluation of the exactness of a measurement or a measuring instrument
Precision
While accuracy indicates how__a measurement is to the actual value, precision indicates how__and measurement is or how_one can make a measurement
Close, repeatable, exactly
What three purposes do significant digits serve
1- they determine the important digits you need to record when making a measurement
2- they indicate the precision of your measurement
3- it helps scientists to report measurements honestly
The__of a measurement consists of all the certain digits +1 estimated digit
Significant digits
When using significant digits the estimated digit is given in?
Tenths of the smallest subdivision on the instruments scale
Rules for adding and subtracting measure data
1- Measure data must be the same kind of dimension and have the same units before they can be added or subtracted
2- The sum or difference of measured data cannot have greater precision than the least precise quantity in the sum or difference
3-The product or quotient of measured data cannot have more significant digits in the quantity with the fewest significant digits
4- The product or quotient of a measurement and a counted number, conversion factor, or defined value has the same number of decimal places, or same precision, I see original measurement
5- in compound calculations, do not round off at the intermediate steps
** five steps in problem-solving**
1- read the problem
2- determine the method of solution
3- choose the specific tools to use
4- set up the problem, estimate, and calculate
5- check and format
+
-
Least precise
•
/
Least significant figure
•
/
With counted number
Go to the decimal place
Density equals
D=m/v
Volume equals
v=m/D
Volume units are always
Cubic length measures
