Hills - the ruse?

neilcooper

Actually, I think you might be the one needing the schooling.

45º is NOT 26.5% gradient. 45º is actually 100% gradient.

Maybe you meant the other way around?

Think of it this way, the percent grade is the rise as a percentage of the level distance.

Lets say you are about to travel up a hill from sea level. The summit of the hill is 50m above sea level. Lets also assume you are traveling in an easterly direction (you'll see why in a moment).

Assume you have GPS that is perfectly accurate (not invented yet) and at the summit it tells you that you've moved 50m east. You've moved the same amount vertically as you did horizontally. The horizontal distance was 100% of the vertical distance. 100% grade. If you draw 2 lines on a piece of paper that are the same length, one horizontal & one vertical and then draw a third line to join them up (forming a triangle) the angle from the horizontal to the line you drew last is 45º. Therefore a 100% grade is 45º.

The sharpest hill you can have expressed in terms of degrees (angle) is 90º. Not really a hill actually, more like a vertical cliff face.

However if grade is expressed in terms of percentage it can be a lot more than 100%.

Spider1977

Veloflash as I'm a professional forester who uses one of these instruments nearly every day I do know what I'm talking about!

The CLINOMETER does not need knowledge of any distances to measure slope - you simply look through the instrument up the slope. Also it has a degrees and percentage slope scale on it. The most common ones are made by Suunto, you can go to their web site and have a look.

If you want to measure the height of something (in my case a tree), then of course you need to know the distance from the base of the tree. Then, through trigonometry you can calculate the height.

I suggest you stick to riding your bike!

VeloFlash

I have been riding my bike in the nearly four years it took you to reply the second time!

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VF

"Remember, even if you win the rat race, you are still a rat"

neilcooper

Long enough to now understand the difference between degrees & percentage gradient?

Sillyoldtwit

I do enjoy a good fight, especially when I'm at the ringside like this. Tyson

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neilcooper

Not much of a fight goin' really. More like 'The Sounds of Silence".

Silence frequently occurs when someone's ego is just a tad bigger than their capacity to realise or acknowledge they don't know everything, or have made a mistake or ....

neilcooper

Come back Velo, it was all in good fun.

frenchyge

....or when it's been 4.5 years since the conversation has had any relevance and one party has decided to just let it go....

(echoes) ...let it go...

(echoes) ...let it go...

(echoes) ...let it go.

neilcooper

Firstly, I had clicked on his profile and noticed that he hadn't posted at this forum since 24th of May which was only a day or two after my last comment to him. I just hated to think I may have been the reason he was staying away (or at least stopped posting). It was my peace offering.

Secondly, in a thread on the subject of hills, the discussion of gradients will be relevant even ten years from now. If you think the thread should die, why bump it?

mikesbytes

I've driven a car up Baldwin st and you feel like you are going to flip over.

http://en.wikipedia.org/wiki/Baldwin_Street,_Dunedin

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