at what altitude is gravity no longer strong enough to pull an average human 175lbs to the earth's surface

Answer 1

Gravity also decreases with altitude (since greater altitude means greater distance from the earth's centre). All other things being equal, an increase in altitude from sea level to the top of Mount Everest (8,850 metres) causes a weight decrease of about 0.28%. It is a common misconception that astronauts in orbit are weightless because they have flown high enough to "escape" the earth's gravity. In fact, at an altitude of 250 miles (roughly the height that the space shuttle flies) gravity is still nearly 90% as strong as at the earth's surface, and weightlessness actually occurs because orbiting objects are in free-fall.

Answer 2

As most people wrote - The gravitational attaction between two masses extends out infinitly (nothing to do with atmosphere!). If the man and the Earth were the only two objects in the Universe then your answer would be "there is no such distance/altitude". But of course there are other masses and thus other other forces acting on the man. The moon and the sun are the major players here. your question might more rightly be posed how far must a man be (of any mass) above the Earth before the pull of the Earth's gravity will no longer be great enough to pull him back to Earth?
There are several answers to even this question as there is a point where this man could go towards the moon and the moons pull would over take the Earth's and another where the sun's pull would take over. A liberation point is where the pull of the Earth and some other body is exactly the same. See http://www.ir.isas.jaxa.jp/SPICA/h2l2_spie/node6.html for more.

Answer 3

Any two objects will pull on each other. A bowling ball has a very small gravitational attraction. The strength of the attraction diminishes at the square of the distance.

However, even if you are very very far away, there's still a very small force. It might take a very long time before you would be pulled to Earth, but it would still happen. In practicality, however, if you were far enough away, you would more likely be pulled somewhere else, such as our sun.

However, if you travel around the earth, it works sort of like when you throw a ball. If you could throw a ball fast enough (and there was no resistance to to air), the ball would fall towards the center of the earth, but it would "miss" because it had traveled far enough around the circle. This is what being in orbit means.

If you wanted to put an object into permanent orbit with no corrections needed, it would be very difficult. Even when you go very high, there's a minute amount of air particles with which you would collide. These would slow you down over time so that you would eventually fall back to Earth.

Answer 4

No such altitude exists. The earth's gravity extends throughout all space. But if the person is moving orbitally about the earth with appropriate velocity, any altitude would do, provided that the air resistance can be ignored (which is the case at altitudes above 100 miles or so).

Answer 5

there is no actual distance/altitude that gravity will not be strong enough to pull, with planets and moons being all around us, however there is such thing as the force of gravity between two planets having the same pull on each other therefore seeming to reduce the "net" gravitational pull between them to zero.. for example this happens at around 9/10ths the way to the moon or about 225,000 km's away from the earth.

Answer 6

In theory gravity between two object extends to infinity. It isn't so much the height that lets spacecraft leave earth's orbit, its the velocity. Keep in mind that we are not only subject to earth's gravity, but also the sun's.

Answer 7

there is no distance that a person couldn't be pulled from. The sun pulls the earth from 93 million miles away. Any two bodies will pull on eachother.

Answer 8

You know....it doesn't matter what wieght you are really. It's all in the matter if you are in the atmosphere or not. I am pretty sure that if you are in Earth's atmosphere Earth will pull you down. But outside of the atmosphere there will be no gravity except the pull on EXTREMELY enormous objects.

Answer 9

It depends on how fast they are moving in orbit and what else is around. If they are not in orbit, and on the opposite side of the earth as the moon is, it's probably about 1 million miles. If the person is between the earth and the moon, it's perhaps120-150,000 miles.

Answer 10

I think it is about 60 miles up.