1.4 Graphing Motion

Position vs. Time Graphs

A position vs. time graph visually represents how an object's position changes over time. It consists of the object’s position (${x}$) being plotted on the ${y}$-axis while the time (${t}$) being plotted on the ${x}$-axis.

The location of a point on the graph represents the position of an object at a certain time. A point above the ${x}$-axis is a positive position while a point below the ${x}$-axis is a negative position. The slope of the graph shows the object’s velocity at a certain period in time. A positive slope is a positive velocity and vice versa. The concavity of the graph shows the object’s acceleration at a certain point in time. A concave up graph shows a positive acceleration while a concave down graph shows a negative acceleration. For AP Physics 1, only qualitative analysis of a concave up graph will be needed and you will not be asked to calculate the acceleration on a position vs. time graph.