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studiot

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studiot last won the day on December 5

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  • Location
    Somerset, England
  • Favorite Area of Science
    applications of physical sciences
  • Occupation
    Retired Technical Consultant

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  1. Our Math teacher worked on a weekly cycle. He didn't need, use a textbook except to set homework. I will start the cycle on a Friday. On Friday he picked up the textbook and looked at the set questions for the section/chapter he had been teaching that week. He picked out several questions saying do questions 3,5,6, and 9 or whatever. The other subject teachers knew to avoid weekends for homework. On Monday he would pick up the chalk, stand poised at the blackboard and say OK Smith, question 3 start me off. He would then write on the board whatever Smith said and the rest of the class were expected to comment if they disagreed. Once Smith had a correct start he would switch to Jones for the next step and so on until the answer was written on the board. In this way the whole class worked collectively through all the questions sometimes into Tuesday as well. He said, "I don't mark homework, you mark your own. At this stage you are old enough to realise the only person you can cheat is yourselves." On Tuesday/Wednesday he would walk up and down in front of the board expousing that week's theory and writing it on the board in his own way from memory. We would copy it down (enough time was given unlike at university). We could also stop him and ask for clarification or challenge a mistake at any point. He would always explain the point and not move on until it was clear. Thursday and Friday we would work collectively through example questions he dreamt up on the spot, in much the same way as the homework set on Friday. His comment on the textbook, "Now you are in the senior class you may be pleased to see that the (numerical) answers are in the back of the book. You may think that is great but will find it a introduces its own burden as you will not want to leave a question until you have got that answer."
  2. What is not moving in the horizontal (x) direction in your coordinate system ?
  3. Yes but it's more than just momentum. I think the poster has difficulty deciding what to include in the system, like many folks before him.
  4. The wedge M is moving sideways to the right only. It has zero vertical movement. mass m is moving downwards and to the horizonally to left relative to the floor, but at the same time it is sitting on wedge M so is also moving to the right the same as wedge M. So mass m has a net sideways movement relative to the floor of two motions. Does this help? Hint think about what swansont said about coordinate systems.
  5. +1 We are all working towards showing that with proper analysis the proposed system can be analysed conventionally, as expected once all the details are teased out.
  6. How can I consider curvature flat ? What does this mean? I asked because I am questioning the quote from Quora and your understanding/use of it.
  7. No problem about the clarity I understood the question well enough and that's what discussion in Homework help is for. Yes you are correct that the wedge M slides along the table or floor in the horizontally opposite direction to the mass m. It is important to understand that this happens while the mass m is sliding down the slope. So the motion of the wedge M is simple, but the motion of mass m is complicated because it's total acceleration is the resultant of three accelerations. Can you see what these are ?
  8. Thank you for this information. +1 Obviously my scribe was having a bad hair day since so many misunderstood his scribblings. I didn't say my link supports or does not support any particular source of water vapour. I said it states that water vapour is the biggest single contributor. It doesn't matter how the water got there it all adds up. So consider the skies over a desert termite. How much water vapour is present ? All this discussion is proving is that atmouspheric dynamics is complicated and multifactorial. In the carboniferous period carbon dioxide levels were high as were temperatures. But then so were oxygen levels. Do you consider oxygen a greenhouse gas ? We couldn't have either water or carbon dioxide without it.
  9. So you are using some of that electrical input to stuff the genie back in the bottle, sorry drive the compressor, also inside the box to repressurise the gas cylinder ? The question was not answered, just neatly side stepped. What else are you not telling us ?
  10. So why did you respond by linking to a paper that states explicitly methane is oxidised? I have quoted this once directly from your post but here it is again for your convenience I still think you misunderstood my post and still do. But I am with you on a good deal of your thoughts here.
  11. Seems to me that Your diagram does not show the small block at the top of the wedge , as stated in your words. Why not ? You have not mentioned friction anywhere or conversely smooth contacts. Are we ignoring friction ? What do you understand as the significance of the ratio M/m = k ? Can you describe in words what movements you think could take place ? You should have done this last step before starting force analyses.
  12. Indeed so. That is how a released balloon flies away if the neck is open. But so what, perhaps your rocket is a cylinder of compressed gas. The question still arises how long will the exhaust last ? This proposal of yours reminds me of Edward De Bono's 5 day course in thinking. In his first lecture he has a 1 foot cubical box sitting quietly on a table in front of him, roughly in the middle. About halfway through there is a quiet bang and the box falls over onto its side. The lecturer ignores this, but at the end sets a task to explain how the box fell over by itself during the next four days.
  13. I blame Apple myself (Along with the second deadly sin)
  14. Thank you for your clarifications. On to my next questions. I understand you are firing a rocket engine inside the box. Since no air is allowed to enter what are you using for oxidant ? How much of the 14.6 kilos is fuel and oxidant and how long will that last in time ?
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