Cats that fell from two to seven stories up mostly landed feet first. Above that, however, cats used a different technique. Instead of positioning their legs straight down as they fell, they splayed out like a parachuter. And landed belly-first instead. Chest trauma, like a collapsed lung, or broken rib is more common with this landing method. But the risk of breaking a leg is much less. So, how do cats somehow subconsciously know how to land? It has to do with a physics phenomenon called terminal velocity.
At first, the cat plummets faster and faster under gravity until she's fallen the equivalent of five stories. At that point, she hits constant terminal velocity at kilometers per hour. She's now in free fall where air friction counteracts her acceleration under gravity. So terminal velocity defines the speed that a rock sinks when you drop it in the water.
But they can increase their speed tremendously by orienting their head towards the Earth — diving towards the ground. The gravity of the Earth pulls at you with a constant acceleration of 9. The opposing force of the atmosphere is called drag.
Terminal velocity, a rather chilling term, describes the velocity at which drag force from the air becomes equal to the force from the weight of an object, and thus the object no longer accelerates and consequently velocity remains constant. The greater an object's cross-sectional area and the less its mass, the lower the terminal velocity and the sooner it's reached.
Fortunately, her fall was broken by a children's playhouse. In very high falls, bodies can reach terminal velocity, the speed at which air resistance becomes so high it cancels out the acceleration due to gravity.
Once at terminal velocity, you can fall as far as you like and you won't gather any more speed.
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