The shutter speed varies the amount of light on the sensor at the back of the camera. A fast shutter speed will give you a more detailed image. When capturing a moving object in an image, you should use a slow shutter speed, as it allows in more light, to capture the moving object.
The images below are examples of when a slow shutter speed has been used to capture moving objects.
The images below are examples of when a slow shutter speed has been used to capture moving objects.