4 ms·
To be clear, they gave you the radius of the earth here, if you didn't already know it by heart? Otherwise, I'm not getting how you could solve this problem (a
by jnbiche 9y ago
To be clear, they gave you the radius of the earth here, if you didn't already know it by heart? Otherwise, I'm not getting how you could solve this problem (assuming they didn't give you the angle that the arch formed, for example).
- ivanbakel 9y agoYou don't need to know the radius of the earth unless you're asked for a numeric answer. The rope is 2 * pi * 10km longer than the Earth's circumference, since its radius is 10km more.
- jamesmaniscalco 9y agoI think this is the wrong interpretation; your answer would be correct if the rope were hovering at a height of 10 km along the full length. My interpretation is that the rope is pulled taut to a height of 10 km at a single point, so that it runs in a straight line to the horizon in either direction and lays on the ground the rest of the way; this is also relevant to the question of longest line of sight from a given height.
- jnbiche 9y agoActually, it's a different question. Check out the second diagram linked to below: https://news.ycombinator.com/item?id=14863949 https://news.ycombinator.com/item?id=14863949 So yes, you could supply the answer in terms of r radius, but you do need to know the radius unless I'm missing something obvious.
- ivanbakel 9y agoThat diagram wasn't posted by the GP.
- jnbiche 9y agoYes, but I only posted that so you'd see which problem the GP is referring to: the second one. Unless somehow the rope is some special kind of non-flexible rope that always assumes the shape of a circle.
- ivanbakel 9y agoWhat makes you think that's the problem the GP was referring to? They haven't posted at all again in this thread to confirm exactly what was meant.