Motion blur and exposure questions

inbal

HI,
I am really trying to get to the bottom of things is vray and I have a few questions:

in the CameraPhysical tab, you can turn it off but you can also turn of the Exposure- what is the difference.
in one of Asgvis tutorials it was said that when the exposure is down, all the other parameters of the F number and shutter and so on do not effect anything in the scene- so what is the differences between them?
In the vray book it is said that the shutter speed effects the motion blur of camera and objects...
since when do we have moving objects in sketchup?
and how do I achieve a motion blur with the camera?

thanks for answering