Timeline for Can Oberth bike? Is biking up and down a series of hills a good real-world analogy for understanding either the Oberth effect and/or gravity drag?
Current License: CC BY-SA 4.0
18 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 10, 2021 at 0:29 | comment | added | Stu Smith | Based on my years of pedaling through hilly country, I'm convinced that nothing loses energy faster than a bicyclist transitioning from downhill to uphill. Exasperating! | |
| Oct 9, 2021 at 22:29 | answer | added | wistlo | timeline score: 2 | |
| Jan 8, 2021 at 5:23 | comment | added | SF. | @uhoh I think a more intuitive example would be a car moving on flat surface, with friction. You start from a stop, and you are allowed to floor the accelerator twice, for 3 seconds every time, choosing the moments yourself. Floor it once, come to a stop, repeat, come to a stop. Check the distance. Now repeat, but just hold the accelerator for 6s from the beginning. The time it takes until you stop is the same (or even shorter) as the two segments in the first case, but you'll cover much more distance, because during the first half of the time you're moving at a significantly higher speed. | |
| S Dec 28, 2020 at 2:01 | history | bounty ended | CommunityBot | ||
| S Dec 28, 2020 at 2:01 | history | notice removed | CommunityBot | ||
| Dec 21, 2020 at 11:37 | comment | added | uhoh | @SF. I think so too, that's why the word "frictionless" appears in the bounty message. Since I don't bike very fast but use a nice bike, most of the time "frictionless" is a good approximation for me as well. | |
| Dec 21, 2020 at 10:43 | comment | added | SF. | This would work if air drag wasn't a viscous friction (proportional to velocity). It would work great in conditions where friction is low, but on bike increasing peak velocity will increase the losses the most. | |
| Dec 21, 2020 at 9:54 | answer | added | cmaster - reinstate monica | timeline score: 0 | |
| Dec 20, 2020 at 4:56 | answer | added | Camille Goudeseune | timeline score: 6 | |
| S Dec 20, 2020 at 0:28 | history | bounty started | uhoh | ||
| S Dec 20, 2020 at 0:28 | history | notice added | uhoh | Improve details | |
| Oct 1, 2020 at 17:11 | answer | added | SE - stop firing the good guys | timeline score: 2 | |
| Aug 19, 2020 at 11:23 | comment | added | uhoh | @asdfex I think this is on-topic and suitable for either site, in that case OP simply chooses the community they'd prefer to receive answers from and where they think it will fit in with other posts. I'm trying to find if the bicycle analogy can be used to help explain Oberth or gravity drag, and I feel this will be of more use here in Space SE where both are oft-discussed topics. I think if nobody can muster an answer here that's supported by math, I'll post one myself just to make sure the results are conclusive. | |
| Aug 19, 2020 at 11:20 | comment | added | asdfex | Isn't this question more suited on Physics SE or even Bicycle SE? | |
| Aug 19, 2020 at 11:20 | answer | added | asdfex | timeline score: 2 | |
| Aug 19, 2020 at 9:00 | history | tweeted | twitter.com/StackSpaceExp/status/1296009020818563072 | ||
| Aug 19, 2020 at 1:32 | history | edited | uhoh | CC BY-SA 4.0 |
edited title
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| Aug 19, 2020 at 1:26 | history | asked | uhoh | CC BY-SA 4.0 |