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chrisbentley349

Day #52: Third Rest Day in Minneapolis

The W hotel in Minneapolis is in the Foshay building, which is a classic 30 storey skyscraper build in 1928. It has an open air viewing deck:


Had a lovely conversation at lunch with a RN (Registered Nurse) named Julia from San Fransisco. She volunteers for a non-profit tour guide company and offered to give me a walking tour when I get to the West coast :-)


Physics sidebar on climbing hills

When you're riding on flat ground gravity hardly affects you. Gravity pulls you to the Earth, but the ground pushes back and they cancel each other out. On a flat ride you're mostly fighting air resistance, but when we start to ride up a hill, we have to fight against air resistance and gravity... the steeper the hill the more we're exposed to gravity's pull:


If we go 10 feet along the horizontal and only climb a few inches, that is a very small slope. We say it's a shallow slope. If we go 10 feet along and climb 10 feet, that is almost too hard to bike up. We say it's a steep slope:



If you know you have to climb a big hill, the longest path up will have the smallest slope, because you're spreading the climb across a bigger distance. Instead of tackling the climb all at once, you're breaking it into lots of small inclines. You will ride farther, but not so steep, which is probably a good tradeoff:

If I'm climbing up a hill that is too tough, I start to weave back and forth across the road, making sure there are no cars... Here's what it looks like in my Sports Tracker app when I'm on a steep hill:


If we pretend I'm riding along equilateral triangles, we can see how much that helps with the steepness. The path straight up the hill is 4 sides long. The winding path is 6 sides long, so the curvy route is 6/4 = 1 and 1/2 times longer. This makes the slope be 4/6 = 2/3 as steep. Not bad :-)


By switching back and forth more and more, you can make a big slope turn into as small a slope as you like. So, this way you can ride up any hill in the world :-)

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2 Comments


Nof KID
Nof KID
Jul 23

The conversation with Julia sounded so nice! That sure makes intuitive sense about weaving up steep hills... Did you get good groceries? -Nof

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Fengmei Zhao
Jul 22

Feels like our graphics classes, a lot of calculations on “slope” :-). Again, even flawless plans many times need to be reviewed and redesigned. We are looking forward to your next summer riding from the midpoint. Fly back and meet us on white mountains?

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