Kinematics and Describing Motion Flashcards

A set of vocabulary flashcards covering the fundamental concepts of kinematics, including displacement, velocity, uniform motion, and graphical analysis.

Kinematics

The mathematical description of motion without regard to its causes, derived from the Greek word "kinema" meaning movement.

Horizontal Motion Sign Convention

Movement along the x-axis where right is positive ($x > 0$) and left is negative ($x < 0$).

Vertical Motion Sign Convention

Movement along the y-axis where upward is positive ($y > 0$) and downward is negative ($y < 0$).

Distance ($d$)

The total path length traveled by an object; it is always a scalar and non-negative value.

Displacement ($\Delta x$)

The net change in an object's position, calculated as $\Delta x = x_f - x_i$; it is a vector quantity that includes direction.

Average Speed

A scalar quantity always expressed as a positive value, defined as $\frac{\text{Total Distance}}{\Delta t}$.

Average Velocity ($v_x$)

A vector quantity whose sign indicates the direction of motion, defined as $v_x = \frac{\Delta x}{\Delta t} = \frac{x_f - x_i}{\Delta t}$.

Slope of a Position-versus-Time ($x-t$) Graph

Represents velocity ($v_x$); the steepness indicates speed, the sign indicates direction, and it is measured in physical units of $\text{m/s}$.

Uniform Motion

Motion along a straight line at a constant velocity, characterized by equal displacements occurring in equal time intervals.

Position Equation for Uniform Motion

The formula used to find final position: $x_f = x_i + v_x \Delta t$.

Area Under a Velocity-versus-Time ($v-t$) Graph

The physical displacement ($\Delta x$) for a given time interval, calculated in units of meters ($\text{m/s} \times \text{s} = \text{m}$).

Instantaneous Velocity

An object's velocity (speed and direction) at a specific instant in time $t$, corresponding to the slope of the line tangent to the curve on an $x-t$ graph.

Instantaneous Speed

The magnitude of the instantaneous velocity, denoted as $|v_x|$.

Turning Point

A point where an object is instantaneously at rest ($v_x = 0$), represented on an $x-t$ graph by a horizontal tangent slope.