Answer:
1) in a motion map the arrows point in which direction the object is moving, but if there are other arrows in the map (like forces and such) those may point in other direction, so if only movement (velocity) arrows are depicted, this is true.
2) True, as "longer" is the arrow, bigger is the magnitude represented (again, arrows may depict other things than velocity)
3) If only velocity arrows are depicted, this is true, because the velocity is zero, then there is no arrow of velocity.
If other arrows are depicted, like acceleration or force, those may be in there in regards that the object is not moving.
