Shutter Speed

By using a slower shutter speed the main focus such as a person, moving car, horse running will be sharply in focus whereas the background will be blurred. Using a faster shutter speed could work with a person or horse running however it will not be as useful to give them same finished image on a fast moving car. The shutter speed needed for a shot depends on how much light there is, and how fast the required image is moving.

Example 

If there was a fast moving car what would the shot require in the day time?

The required shot would need a wide aperture with a short exposure, and a slow shutter speed. 

Although the required aperture, exposure, and shutter speed gains the required shot, this can also make the car look as if its moving slower than it is. Changing when the image is taken such as at night rather than in the day which would require a long exposure can make the car look like its moving fast, and add a blurry effect to the image.