Throwing Stuff Down A Mineshaft

Nice one!Now a theoretical question: what would you expect to happen with something they throw in the hole if it was a hole that went all the way to other side of the earth? (Let's just ignore the hot core of the earth and assume it's cold and solid, with the hole going right through it.)

You're on the right track, but you must ask yourself when exactly its acceleration starts to decay...(Added by edit: it has something to do with WHY the acceleration starts to decay at a certain moment.)Edited by Parasomnium, : No reason given.

Nearly spot on! You only need to explain why it overshoots less far each time. (Hint: what happens if there's no air?)

Are you sure about this? I would have thought that as long as you are not in the exact centre of gravity, you would fall toward it, overshoot, fall back, overshoot again, etc.

Don't worry, you'll bump into it, no doubt.

If there's no air resistance, there's no reason why it wouldn't fall all the way to the opposite side, to the same height it was released from, and then fall back, again to the same height, etc. In other words, without air resistance, it would endlessly oscillate between both extremes without diminishing amplitude.You could rescue the goat by just grabbing it the moment it pops back up. You could also wait a few hours to see it pop up repeatedly, and then grab it, because it would pop up just as high each time. Of course, without air, you wouldn't really be rescuing it, because it would've suffocated ^*, but you get the idea... * and so would you, by the wayEdited by Parasomnium, : No reason given.Edited by Parasomnium, : No reason given.

My mathematical skills are rather rickety, so I probably couldn't follow your explanation.But I was under the impression that you can do the maths for the gravitational effects of any massive object by treating it as a point mass. The point mass of a hollow sphere would be located in its exact centre (its centre of gravity), in which case we would be talking about a similar situation as that of our hypothetical hole in the earth. As long long as the path through the centre of gravity is free, you would just oscillate along this path between extremes, inside the sphere, as you would through the hole.But I'm open for suggestions that would convince me otherwise.

I'm not convinced that this would be what happened. If the forces from all sides cancel out, as you explain, then the net force on you would be zero.The rest of what you say makes excellent sense.

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"Ignorance more frequently begets confidence than does knowledge: it is those who know little, not those who know much, who so positively assert that this or that problem will never be solved by science." - Charles Darwin.

Thanks for enlightening me, Cavediver, I didn't know that. If I'm correct you're a physicist of some kind (I'm too lazy to look it up in old messages), so I'll take your word for it.

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"Ignorance more frequently begets confidence than does knowledge: it is those who know little, not those who know much, who so positively assert that this or that problem will never be solved by science." - Charles Darwin.