Physics Lecture: Reference Frames, Displacement, and Velocity

Vocabulary flashcards covering key terms related to reference frames, displacement, distance, speed, velocity, scalars, and vectors.

Reference frame

A system used to define where an object is located, describing its position relative to other objects.

Origin

The zero point ($0$) in a coordinate system.

Delta ($\Delta$)

The Greek letter used as a symbol to represent a change in a quantity, such as a change in position ($\Delta x$).

Displacement

A vector quantity describing how far an object is from its starting point regardless of the path taken, calculated using the formula $\Delta x = x_f - x_0$.

Distance

A scalar measurement of how far an object has traveled, which can only consist of positive values.

Speed

A scalar quantity defined as the ratio of distance and time.

Velocity

A vector quantity giving both the magnitude and direction of an object's motion, defined mathematically as $v = \frac{\Delta x}{\Delta t}$.

Average velocity

The total displacement divided by the elapsed time for a trip, represented by the symbol $\bar{v}$.

Instantaneous velocity

The velocity of an object at a very brief moment in time, calculated as $v_{\text{instantaneous}} = \frac{\Delta x}{\Delta t}$ as the time interval $\Delta t$ approaches a tiny value close to zero.

Scalar

A quantity that has only a magnitude, which is a numerical value (such as time, distance, or speed).

Vector

A quantity that has both a magnitude and a direction (such as displacement or velocity).