PHYS 203 Chapter 1: Introduction to Physics and Measurement

Vocabulary flashcards covering the fundamental units, dimensional analysis, unit conversions, and significant figure rules from the PHYS 203 introductory lecture notes.

Units

Allows for the description of physical phenomena in mechanics and the communication of measurement results.

Length SI Unit

meter ($m$)

Mass SI Unit

kilogram ($kg$)

Time SI Unit

second ($s$)

Temperature SI Unit

Kelvin

Electric Current SI Unit

Ampere

Luminous Intensity SI Unit

Candela

Amount of Substance SI Unit

mole

Dimensional Analysis

A practice where both sides of an equation must have the same dimensions, using fundamental dimensions of Length [L], Mass [M], and Time [T].

Density

The ratio of mass to volume ( ext{Density} = rac{ ext{Mass}}{ ext{Volume}}), with dimensions of $M/L^3$ and SI units of $kg/m^3$.

1 mile

$16091\,m$ or $1.6091\,km$

1 meter

$39.371\,in.$ or $3.2811\,ft$

1 foot

$0.30481\,m$ or $30.481\,cm$

1 inch

$0.02541\,m$ or $2.541\,cm$

Uncertainty

Inherent in every measurement, potentially caused by the apparatus, the person taking the measurement, and/or the number of measurements made.

Significant Figure

A reliably known digit that depends on the measurement tools, operator, or reporting method.

Significant Figure Rule #1

In numbers without zeros, all digits are significant (e.g., $3.5781$ has 5 sig figs).

Significant Figure Rule #2

All zeros between digits are significant (e.g., $4.028$ has 4 sig figs).

Significant Figure Rule #3

Zeros to the left of the first digit are placeholders and are NOT significant (e.g., $0.0567$ has 3 sig figs).

Significant Figure Rule #4

In a number with a decimal point, all zeros to the right of the last number are significant (e.g., $75.00$ has 4 sig figs).

Significant Figure Rule #5

In a number without a decimal, zeros to the right may or may not be significant; scientific notation should be used to avoid confusion (e.g., $1.8 imes 10^3$).

Multiplication/Division Sig Fig Rule

The number of significant figures in the final product or quotient is the same as the number of significant figures in the least accurate of the factors being combined.

Addition/Subtraction Sig Fig Rule

The number of decimal places in the result should be the smallest number of decimal places of any term in the sum or difference.

Standard International Number Notation

When writing numbers with many digits, spacing in groups of three is used with no commas (e.g., $25\,100$).