How fast does a free-fall parachutist fall?

Question

When a free-fall sky diver jumps from a plane...how fast does he fall before the force of gravity draws him closer to ground?

Answer 1

Gravity is regarded as a constant causing acceleration of 9.81 m/s per second on Earth and will affect a skydiver jumping from any altitude.  A terminal (maximum) velocity is reached after about 15 - 20 seconds when the air-resistance of the diver balances out the effects of gravity.  For a skydiver in a free-fall position with a semi-closed parachute, this is about 120 mph (195 km/h or 55 m/s), but if the diver pulls in his limbs, this increases to about 200 mph (320 km/h or 90 m/s) and in the head down position, competition skydivers can reach even higher speeds.

However, in 1960, Captain Joe Kittinger made a parachute jump from a helium balloon at 102,800 feet (19.47 miles or 31,333 m).  At this high altitude, where the atmosphere is thinner and therefore drag reduced, he reached a speed of 614 mph (988 km/h or 274 m/s) and in doing so set the current world record which would seem very unlikely to ever be beaten.

Answer 2

You have some major problems with your understanding of gravity and falling.

The parachutist is being attracted to the ground by the force of gravity even while he is in the plane waiting to jump. The plane provides an opposite upward force to stop him falling . Sounds a little crazy I know, but imagine he is sitting on the floor of the plane, he doesn't fall to the ground because the floor prevents this. This is Newton's third law.

Immediately he jumps out, he loses the force that the floor was exerting upwards on him, and he immediately starts to fall towards the earth, theoretically accelerating downwards at 9.8m/s². The air surrounding the parachutist provides some resistance to his falling at this acceleration. As the parachutist accelerates downwards, his velocity increases and so the resistance from the air increases until the upward force from the air resistance exactly equals his downward force from gravity (technically his weight). At this stage the parachutist is said to have attained terminal velocity. He continues to fall towards the earth at constant velocity, his acceleration downwards is 0.

The parachutist is in free fall from the instant that he jumps from the plane until he opens his chute.