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Okay, how many of us have heard of a cat surviving a fall from hundreds of feet? Every once in a while a news story will pop up telling of some skyscraper-dwelling cat that amazingly walked away after some kid threw it over the balcony. (Or maybe it just fell.) But have you ever wondered exactly how the cat survived?

The answer is actually an interesting study in physics. If you recall, the acceleration of a falling body (gravity) is 9.8 meters per second squared, or 32 feet per second squared. A quick conversion tells us that a falling mass is increasing its speed about 22 miles per hour for every second it falls. So a cat (assuming he started at zero mph when he fell off the balcony) will be traveling about 22 mph after one second, 44 mph after two seconds, 66 mph after three seconds, etc, etc.  But… any falling mass in the Earth’s atmosphere will reach a terminal velocity (Vt) depending on its weight, mass and shape. Its shape will determine air resistance, hence, a spherical cat will have a higher terminal velocity than a rectangular one.

Well, since there are no spherical or rectangular cats, we have to estimate this terminal velocity for cats. I just read that an actual cat’s Vt is about 60 mph. I guess a group of rogue scientists calculated this by throwing a few cats off a building and timing their descent until they hit the ground. Or maybe they’re just estimating.

So why is a cat’s terminal velocity only 60 mph whereas a fat human’s would be about 120 mph? The answer here is more of a study in biology than physics. A cat has a very sophisticated inner ear and sense of balance. That’s why they usually land on their feet after a fall. But this same sense that innately tells a cat that it’s falling also tells it that it is accelerating — and then when it’s stopped accelerating (reached its Vt). When this happens, a cat will flatten itself out, thus creating a much higher air drag (almost like a parachute or flying squirrel). Then it’s velocity will actually decrease to such a speed that may allow it to survive the fall.

I think this has been proven (or hypothesized) by studies after the fact from vets in big cities reporting incidents of falling cats surviving. An interesting result is that falling cats have a 10% chance of being killed in falls from two to six stories but their chances of survival are increased twofold when falling from 7-32 stories. I don’t think there has been enough data collected from cats falling more than 32 stories to be statistically significant.

And so it goes.