Wikipedia:Reference desk/Archives/Science/2022 August 8
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August 8
editPhysics Question
editFound this question somewhere, but can't understand, kindly solve it or just tell something- "You along with your 6 friends discovered an abandoned 11m long boat and decided to board it in a single line. The boat started to lose balance from the front and the back, and in that chaos, everyone began to collide with each other elastically while moving with a constant velocity of 0.5 m/s. Eventually, all of you will fall down due to such collisions, but with one particular order of collisions, it will take the longest time for all 7 of you to fall off. Find that longest time period." 103.139.171.71 (talk) 13:07, 8 August 2022 (UTC)
- You're assuming the premise is valid. ←Baseball Bugs What's up, Doc? carrots→ 13:17, 8 August 2022 (UTC)
- That seems like a very convoluted restatement of a classic riddle about ants on a board or on a rod. See the answer to question (A) in the second link for the solution.
- Considering that it is a "gotcha" question where you either see the trick or you don’t, I am inclined to think this is not a homework problem. (And it’s not really a "physics question" either: if anything, "collide with each other elastically" is physically incompatible with "while moving with a constant velocity of 0.5 m/s" unless everyone has the same mass.) TigraanClick here for my talk page ("private" contact) 14:19, 8 August 2022 (UTC)
This is not my homework obviously. Just found it somewhere over the internet unsolved. Also, I am a student whose physics level is yet lower than the question. --103.139.171.71 (talk) 15:21, 8 August 2022 (UTC)
- And you were given an answer by Tigraan above. --Jayron32 15:26, 8 August 2022 (UTC)
- This is no physics question; it's a mathematics puzzle. PiusImpavidus (talk) 08:16, 9 August 2022 (UTC)
- Sure - no argument - but there are a lot of refined mathematical techniques that are widely used by physicists - like partitioning - that we can use to quickly simplify and approximate, provided we can recognize their utility. A pure mathematician might solve directly; a physicist might take a left turn at Albuquerque, assign an effective temperature for the boat, and derive a diffusion-time-constant... then since it has been reduced to a previously solved problem without loss of generality (which the mathematicians will appreciate), the physicist doesn't bother calculating a numerical answer and gets distracted analyzing the quantum-mechanical implications of estimating temperatures for very small numbers of particles. Meanwhile, the mathematicians are converting the problem into some kind of graph-topology in a modular-arithmetic system over commutative rings, and constructing an algebra to represent "collisions" as a linear operator; and the original poster is still looking for an answer measured in minutes and seconds. Different minds have different conceptualizations about what it means to "solve a problem" or "answer a question." Nimur (talk) 15:08, 9 August 2022 (UTC)
- Additionally meanwhile, the machine learning goons are still trying to recruit low-wage data labeling technicians to review six hundred million video clips of people falling off of boats, because they assure us that as soon as they have enough data, their method to estimate the answer will start converging... Nimur (talk) 15:12, 9 August 2022 (UTC)
- The physics part is having a deeper understanding of the meaning of elastic collisions. If the question were more precisely worded, I think it could be a very good illustration of (multiple) very fundamental concepts. It can then be modified to demonstrate the limits of inelastic collisions (my demo for that concept would be with uniform acceleration, such as if stacked vertically on Earth). SamuelRiv (talk) 16:26, 9 August 2022 (UTC)
- Sure - no argument - but there are a lot of refined mathematical techniques that are widely used by physicists - like partitioning - that we can use to quickly simplify and approximate, provided we can recognize their utility. A pure mathematician might solve directly; a physicist might take a left turn at Albuquerque, assign an effective temperature for the boat, and derive a diffusion-time-constant... then since it has been reduced to a previously solved problem without loss of generality (which the mathematicians will appreciate), the physicist doesn't bother calculating a numerical answer and gets distracted analyzing the quantum-mechanical implications of estimating temperatures for very small numbers of particles. Meanwhile, the mathematicians are converting the problem into some kind of graph-topology in a modular-arithmetic system over commutative rings, and constructing an algebra to represent "collisions" as a linear operator; and the original poster is still looking for an answer measured in minutes and seconds. Different minds have different conceptualizations about what it means to "solve a problem" or "answer a question." Nimur (talk) 15:08, 9 August 2022 (UTC)