Tahaarat

Are hair roots impure?

Q: Is the root of the hair najis? And if so, what does this really mean? Since the hair that the body has naturally shed has the root intact (as opposed to cut hair), do I then assume that all hair that I see on the floor or in the bathroom has a part of it that is najis?

As a consequence, if I am eating soup or drinking water, and some hair falls in, does that make the entire liquid najis? If some fallen hair on the floor sticks to my wet foot, do I have to wash my foot? How exactly is the najasat of the hair root transferred?

Washing an impure floor

Q: I saw urine on the floor so I was wiping it but did not finish it when someone stepped on it but at that time color of water was not like urine but I was not finished. After I finished the same person again stepped on the clean wet floor. Will the floor again become impure or not?