Velocity is the speed and direction an object is moving. In this lesson, we're only going to talk about objects moving in one direction, so only the speed of the object will be changing.

On a velocity vs. time graph, there are two variables. One variable is the time, and the other variable is the velocity of the object. Which of these variables do you think is the independent variable and which is the dependent variable.

Velocity vs. time graphs looks much like position vs. time graphs. You have to look very carefully at the axes. Be sure and read the axes labels!

Let's take a closer look at the parts of a velocity vs. time graph. Click on the words below.

Let's look at some velocity vs. time data to see how it is displayed on a velocity vs. time graph.

Velocity vs. Time Graphs Summary

A velocity vs. time graph shows us how the velocity of a moving object changes with time.

• The steeper the graph, the greater the acceleration.
• A horizontal line means the object is moving at a constant speed.
• A downward sloping line means the object is slowing down.

Click on each line to see a description of the motion being illustrated.