An abrupt deceleration
You freefall at approximately 120 mph. That's the speed at which air resistance is slowing you down to the same extent as gravity is speeding you up. That's around 200 kph. 56 metres per second. The height of the Empire State Building in less than 7 seconds. The height of Big Ben in London in 1.74 seconds.
The wind presses your skin against the underlying musculature, but you're a bit too preoccupied to notice that, usually. The thin plastic goggles are pushed into the skin of your face, leaving marks that will take some minutes to fade once you're on the ground.
The shock of deployment would hurt, which is why a modern parachute is designed to deploy gradually, over a few seconds. Nevertheless, when it deploys, you find yourself abruptly upright and the leg straps dig deeply into your thighs.
Posted by nlvp at August 10, 2006 06:37 PM