How to ask a question using "displaced" when an article is displaced some distance?
Is it "how long was it displaced?" or "how far was it displaced?"
"How far" will ask about distance. "How long" will ask about time.
"How far was this displaced?"
"By about ten meters. It was by the wall, and now it's in the middle of the room."
"How long was this displaced?"
"For about four days. It was moved by a forklift last monday morning."
Note "displaced" usually means "placed at a wrong location". e.g. the object was at the right place, and then was moved somewhere else, where it didn't belong. For normal movement you'd use "moved". (also, the comment about "how far away" - this is about distance from the origin, while your question asks about total travel distance. Say, the crate was moved three times, through all corners of a square room 10x10m size, starting from the corner where it was supposed to be left unmoved. It was displaced by a total of 30m, to a location 10m away.)