Here is one I really want to know!!!?

Question

If you parachute from a plane at 3000 feet and have a specific place to land..would you still land at the place you have carefully planned?..as the world does turn..wouldn't you be off like a couple thousands of a inch?

Answer 1

No, you'd be out by much further, because even though you can steer your parachute your original rotational velocity has diminished due to air resistance. Over a 3,000 foot (900 metres) parachute jump, it is possible to miss the target by as much as 18 inches (450 mm).

You can check this for yourself with a simple test.

1) Stand on a flat, even surface with your feet about 6 inches (150mm) apart.

2) With a piece of chalk, draw around the outline of your feet.

3) Keeping your body as straight as possible, jump directly upwards.

4) When you land, mark around your feet in a different colour of chalk.

5) Measure the distance between the two outlines to see how much the planet has moved while you were in the air.

5) If it's a big difference (greater than 2-3 inches) then you are suffering from "Retrograde Motion Sickness" and should seek immediate medical help.


ADDENDUM : Okay, perhaps I should make it clear that this is not a real answer. Although if leaping up and down on the spot is what gets you through the day then, hey, go for it!!!!!
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Answer 2

You'd have to be incredibly lucky to hit a spot with precision measured in thousandths of an inch. Posters make some good points, most all valid, but keep in mind that as a parachutist, you can direct and control where you land to various degrees if you are skilled. However the most skilled parachutists hit a 6 foot circle as the standard of accuracy. So thousandths of an inch would probably be luck. 4-6 feet might be an achievable goal.

Some posters said the Earth would spin away from you the Earth however does not rotate away from you that much due to the relevance of motion principles. Much like inertia in a car or other moving vehicle and depends on how far above the surface you are. At typical jumping altitudes of 5,000 to 20,000 feet, the effect is negligible. We could also spend a lot of space talking about where wind resistance, your specific drag coefficient, thermal drafts, and other things would place you if you could assume a direct descent.

P.S. Direct descents never happen due to all the external forces acting on a jumper.

Answer 3

Please, everyone, try some science! Yes, the surface of the earth is moving 1000 MPH at the Equator, but so is the air and the airplane. If your airspeed is 100MPH when you jump, then you are moving initially at 100MPH relative to the air. Gradually, air resistance slows that down. It slows down dramatically when you open your parachute. You know the acceleration of gravity. All this time, the air is moving with respect to the ground (wind). You factor all this together and make an educated guess about where and when to jump relative to the target. You can make adjustments with the controls on the parachute as you descend. Beyond the initial calculations, the best way to get good at this is experience (practice).

Answer 4

If you tried to plan your landing precisely, you would have to account for:
the rotation of the earth,
the speed and course of the plane,
the wind speed and direction.
Any one of these would move you far more than "a couple of thousands, (sic), of an inch".

Answer 5

At the equator, the earth is spinning at a rate of ~1000 miles per hour. Of course, so is the parachutist. However, there are would be small corrections that would need to be made to compensate for the earth's movement. The Coriolis force is a force that is related to the movement of the Earth. The parachutist would also be subject to it.

Answer 6

Yes. You will be off by even a mile. It is just not possible to pick an exact spot where you could just jump off the plane and land.

Answer 7

Nope. Used scientific method, experimented, and I therefore conclude that you move as the world does...

WHAT A PAIN... UGH...

Answer 8

Yup. You got it.