Motion in a photograph is capturing the movement of someone or something by changing the shutter speed and sometimes aperture. The slower the shutter speed the more movement you will catch in a photo, however this can cause mistakes if the shutter speed is slow and the object is fast, it may become invisible or very hard to see.
This is an example of motion, it shows the child on the roundabout in good focus, whilst the rest of the photograph is blurred, this shows us that the roundabout is spinning round so it looks like the rest of the world is moving from that perspective.
This is a photo of someone running, it shows motion because we can see where his arms and legs have moved, the ground is also showing movement a bit which looks cool.
This photograph shows a lot of movement, almost all of the characters in the photo show movement and I think the photographer probably didn't use a tripod because the ground is also showing movement which shouldn't happen unless they are moving as well.
This photo shows a lot of movement by using long exposure, the shutter speed was probably very slow for this photograph, meaning that a lot of movement was captured. you can tell this person used a tripod because the lights in the background aren't moving as well.