AP Physics: Representing Motion

motion diagram

a number line showing dots along side it, where each dot represents

slope of a graph

the ration of a graph’s vertical change to its horizontal change (“rise over run”)

area of a graph

the area defined by the graph line (or curve), the horizontal axis, and two vertical lines called “initial” and “final”

“position and time” model

tells us where the object is at different clock times

• position is positive if the object is to the right of or above the origin, negative if to the left of or below the origin

“velocity and time” model

tells us how fast an object is going at different clocktimes

• velocity is positive if the object is moving to the right or upward, negative if the object is moving to the left or downward

displacement between two adjacent pairs on the “velocity and time” table

displacement = average velocity x time interval

equation for final position

x = v (t-t₀) + x₀

• x = object’s position right now

• x₀ = position of the object at the beginning of its motion

• v = constant speed of the object

• t = clock time right now

• t₀ = clock time at the beginning of motion