If there was no wind resistance, would rain kill you?

Question

Talking physics, gravity pulls rain down to the earth. Wind resistance pushes upward slowing the pull of gravity.

If there was no wind resistance, would rain kill you?

Answer 1

I really don't think so.

Answer 2

Good question.

Without wind resistance, there wouldn't be a terminal velocity for the rain drops. They would accelerate indefinitely towards earth. The real question is: can a drop of water kill you at very high speed. I don't believe that a liquid impinging on you can kill you - no matter how fast it travels

Answer 3

Well, if we're talking physics, we'll want to start figuring out some numbers to work with.

Let's assume the cloud that is producing rain is 3,000ft above earth (see bottom of first reference for heights of clouds).  Because I use metric and am lazy, I'm going to say that's about 900m (reference 2, for those who want to follow along).

We're going to assume that water can still form drops as it normally does, etc - the only difference is that there is no air resistance.

The rain drops would accelerate at 9.8m/s^2 due to gravity.  Thus, using kinematics (reference 3):

v(f)^2=v(i)^2+2*a*d

v(f)^2=(0)^2+2*(9.8)*(900)

v(f)=sqr(17640)

v(f)=132.816 m/s

This is about a third of the speed of sound (reference 4).  I don't know if this would be enough to kill - I seem to remember a myth-busters episode in which 100 m/s didn't kill.  However, it would hurt a lot, and that's only one drop.  Being caught in a downpour would probably be deadly.  Further, a 900m cloud is fairly low - according to the first reference, thunderclouds can be as high as 65,000 ft.  Rounding down, this is 19,800m, which, using the same calculations as above, works out to about 623m/s.  This is faster than the muzzle velocity of some guns, which suggests that these raindrops would be deadly.

All of which suggests we should be very thankful that air resistance exists.

(Sorry for the excessive referencing - I was having fun.)  

Answer 4

No, because it is the air itself not moving air(wind) that determines the rate rain falls at.