Who remembers the joke that water falling from the sky will kill people?

Last night, in order to increase my knowledge, I mistakenly joined a doctoral group. I saw a man ask: A drop of water falls freely from a very high place. Does it hurt to hit someone? Or killed?

The group immediately became lively, and discussed various formulas, assumptions, various winds, resistance, gravity, acceleration and so on for nearly an hour.

At this time, I silently asked: Have you never been caught in the rain? There was a sudden silence in the group ......

Then, then I was kicked out of the group.