Can you help me with this question re Ghosts

Maybe when they suddenly appear they have risen from the floor/ground

Presumably, that wall wasn't there when they were alive. But the floor was.

I do recall a ghost story, about an American Navy vessel that was decommissioned and turned into a museum. Somewhere in the states. Tours would go through and a couple of them had been led by a Blonde haired young serviceman. Trouble is, there was nobody like that on the payroll, and he looked a lot like the guy who died on that ship during WW2.

Supposed to be a interdimensional thing.

Not the same physics as here. Why they have troubles moving things.

Think of it this way, try moving around blindfolded. Not as easy as many think. Yet still possible.

LOL! Maybe they are just going through the motions of walking and are actually floating across the floor.

I get this question all of the time 👻

They have no weight.

Because they can fly.