Motion blur is seen in images when the camera is moved during the process of taking the picture. This leaves the picture blurry and warped. Motion blur can also occur from not moving the camera; there can be a fast moving object i.e. a car driving past while the picture is taken - leaving a blurry image of the car. Motion blur gives a sense of fast moving objects in the picture or that the picture was taken at high speeds.
Example of motion blur while a car is present.
To obtain motion blur, we had a member of our group jump while a picture was taken. When the picture was taken while he was jumping, he appeared blurry in the image.