An example of "motion blur" is shown here...this is a great resource for teachers and students.

I've decided to build my own little After Effects Visual Reference Library for when I'm teaching my motion graphics classes and post it here. This is in no way meant to replace the books out on the market when you are teaching...It's more of a visual complement to them.

There is an example of motion blur below that you can play.

A.Motion Blur can be adjusted under the composition settings under the advanced tab.
B. Sets more or less trails

Motion Blur will generate more trails and a more intense blur if the layer is moving faster.

If you would like to use the After Effects project below you can find it HERE

Motion Blur examples at 10 frames, 1 second and 3 seconds.