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If an heavy object (e.g. 10 tons) orbiting around Earth at 370 miles high, is connected with a cable back to Earth, we assumed either Earth is going to pull the mass or vice versa (or it will fall back to Earth). Assuming correct pressure/release/pull can be applied from the ground to prevent the fall, or it naturally starts spinning around in a circular motion - what do you think about its power generation capability?

This was a fun chat between friends, so just wanted to run it by.

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    $\begingroup$ Any object orbiting at an altitude of 370 miles is going to be moving at about 7,500 m/sec. Assuming you could find a strong enough rope, the object would revolve in a quarter of a circle around the attachment point and hit the ground in about 2 minutes (making a large bang when it did so). $\endgroup$ – John Rennie Apr 22 '14 at 9:16
  • $\begingroup$ Comment to the question (v2): In such homework type of questions, OP is encouraged to perform a crude back of an envelope calculation as a sanity check, and possibly include it in the post. $\endgroup$ – Qmechanic Apr 22 '14 at 9:30
  • $\begingroup$ Why do you think orbiting mass generates power? $\endgroup$ – Immortal Player Apr 22 '14 at 9:49
  • $\begingroup$ Any energy you may get from the orbiting object, you will have already lost in getting the object into orbit. And of course then there's the objection @JohnRennie makes, in case you were assuming the object is already orbiting up there (please don't lasso in the moon). Or perhaps you're thinking of an attachment point moving along the surface of the earth, but then the energy losses from the friction needed to keep the attachment point from flying off will quickly slow the object down and the outcome will again be a large bang. $\endgroup$ – Wouter Apr 22 '14 at 11:06
  • $\begingroup$ @john re:bang, Space elevator states "Upward centrifugal force from the Earth's rotation ensures that the cable remains stretched taut, fully countering the downward gravitational pull." $\endgroup$ – Devrim Apr 22 '14 at 16:54
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This would be space elevator type of setup but it is too short to stay in orbit. It should extend beyond the geostationary orbit (~22,000 miles). International space station is a an altitude of ~200 miles and goes around the planet every 90 mins. Even if you build a proper space elevator there is no way to generate more energy than you already use to build it.

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