PHYS1011 Chapter 1: Models, Measurements, and Vectors

Vocabulary flashcards covering foundational physics concepts, SI units, dimensional analysis, significant figures, and vector algebra from Chapter 1.

Physical Theory

A pattern or principle discovered by observing natural phenomena that relates these phenomena.

Physical Law

A physical theory that is very broad and well established.

Idealized Model

A simplified version of a physical system that would be too complicated to analyze in full without simplifications.

Physical Quantity

Any number used to quantitatively describe an observation of a physical phenomenon.

Operational Definition

A definition of a physical quantity that describes a procedure for measuring it.

Second

The SI base unit of time, defined as the time required for $9,192,631,770$ cycles of the radiation corresponding to the transition between the two lowest energy states of the cesium atom.

Meter

The SI base unit of length, defined as the distance light travels in vacuum in $1/299,792,458$ second, establishing the speed of light as precisely $299,792,458\,\text{m/s}$.

Kilogram

The SI base unit of mass, historically defined by a platinum-iridium cylinder kept near Paris, revised in 2019 to be defined in terms of fundamental constants including the Planck constant $h$.

Derived Units

Units obtained from base units using the mathematical relationships that relate derived physical quantities to base quantities.

Unit Consistency

The requirement that all terms in a physical equation must have the same physical units across addition, subtraction, or equality signs.

Scalar Quantity

A physical quantity described completely by a single number representing its magnitude without any direction.

Vector Quantity

A physical quantity that possesses both a magnitude and a direction in space.

Displacement

The simplest vector quantity, representing an object's change in position, drawn as an arrow pointing from its starting position to its ending position.

Negative of a Vector

A vector that has the same magnitude as the original vector, but points in the exact opposite direction.

Resultant Vector

The vector sum formed by combining two or more individual vectors.

Vector Components

The projections of a vector along specific coordinate axes, given by $A_x = A \cos(\theta)$ and $A_y = A \sin(\theta)$, where $\theta$ is measured counterclockwise from the positive $x$-axis.

Magnitude of a Vector

The length or size of a vector, calculated from its orthogonal components using the Pythagorean relation $A = \sqrt{A_x^2 + A_y^2}$.

Significant Figures

The meaningful digits in a measured or calculated value that indicate its degree of precision.

Scientific Notation

A format for writing numbers as a value greater than or equal to $1$ and less than $10$, multiplied by a power of $10$.

SOH CAH TOA

A trigonometric mnemonic for right triangles defining $\sin(\alpha) = \frac{\text{Opposite}}{\text{Hypotenuse}}$, $\cos(\alpha) = \frac{\text{Adjacent}}{\text{Hypotenuse}}$, and $\tan(\alpha) = \frac{\text{Opposite}}{\text{Adjacent}}$.