Today was the first time since a couple of weeks, where I got an impact to the head. it is difficult to explain what happened. I was in a restaurant and wanted to take my daily pills. I layed them town on an empty dish and tried to pick them up directly with my mouth(because my hands were dirty). I forgot that i was wearing a cap at that moment. So I tried to bend down, when suddenly the bill of the cap stopped my head as it hit the table. Maybe this doesn't sound bad for you, but I was moving down pretty quickly (About 1.5 or 2 m/s) and after the incident I got a strange feeling in my head.

I don't know excactly what numbers you need to do the calculation, but i give you all I can remember. There is a gap between my forehead and the innerside of the cap (about 3mm). I guess this cushioned the impact at least a bit.The table itself didn't move at all of course. my head was 30cm away from the table when it started to move down.