1.1.2 Definitions Flashcards
Physical Quantities and Units, and Accuracy, Precision, and Significant Figures, and Approximation
Physical Quantites
Properties or attributes of objects or phenomena that can be measured.
Examples of Physical Quantities
Length, mass, time, and temperature
Units of Measurement
Provide a standard for measuring physical quantities and ensure consistency in communication
SI Units
Base Units: length (meters), mass (kilogram), time (second), electrical current (ampere), temperature (kelvin), amount of substance (mole), luminous intensity (candela)
Derived Units: velocity (m/s), force (N=kg*m/s^2)
Conversion Factors
Used to change a quantity from one unit to another
Dimensional Analysis
A method used to check the consistency of equations and convert units
Accuracy
The closeness of a measured value to the true or accepted value
Precision
The degree to which repeated measurements under unchanged conditions show the same results
Accurate But Not Precise
Measurements are close to the true value but vary widely
Precise But Not Accurate
Measurements are consistent with each other but far from the true value
Precise And Accurate
Measurements are both close to the true value and consistent with each other
Neither Accurate Nor Precise
Measurements are neither close to the true value nor consistent
Significant Figures
Digits in a number that are important for indicating the precision of the measurement
Rounding Addition and Subtraction
Round the least number of decimal places in any of the numbers used
Rounding Multiplication and Division
Round to the same number of significant figures as the number with the fewest significant figures
