Slopes
2007-06-13
Something Dragon said (or more to the point, flippantly challenged me to) has got me thinking.
On its page on slope, Wikipedia is quite clear that a road sign that says '1 in 10' (or 10% as it would appear now) denotes a slope of one unit rise per ten units of horizontal travel. I had always assumed that, until I got into a discussion with a maths lecturer at sixth form college who was adamant that it actually meant one unit rise per ten units on the sloped surface.
In case you can't see it, the former is slightly steeper. If you don't believe me, you'd best not say so, in case I feel like I should prove it.
Wikipedia isn't always to be trusted, but then nor are lecturers. Anyone want to vote for their favourite? I was pretty much won over by the lecturer, until I found that Wikipedia agreed with me. Better still, anyone know of an authoritative source on it? (The highway code website just describes the 20% sign as 'a steep hill', and makes no effort to explain why 20% should denote 'steep').
On its page on slope, Wikipedia is quite clear that a road sign that says '1 in 10' (or 10% as it would appear now) denotes a slope of one unit rise per ten units of horizontal travel. I had always assumed that, until I got into a discussion with a maths lecturer at sixth form college who was adamant that it actually meant one unit rise per ten units on the sloped surface.
In case you can't see it, the former is slightly steeper. If you don't believe me, you'd best not say so, in case I feel like I should prove it.
Wikipedia isn't always to be trusted, but then nor are lecturers. Anyone want to vote for their favourite? I was pretty much won over by the lecturer, until I found that Wikipedia agreed with me. Better still, anyone know of an authoritative source on it? (The highway code website just describes the 20% sign as 'a steep hill', and makes no effort to explain why 20% should denote 'steep').
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