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exchemist last won the day on October 28 2020

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About exchemist

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    Rowing, choral singing, classical music, history and philosophy of science

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  1. This person is mentally ill, having posted exactly the same stuff elsewhere 18 months ago, under the name Tailspin: http://www.thescienceforum.com/biology/49276-what-mechanics-perception-does-limit-our-perception.html
  2. Shakespeare. It's called "The Seven Ages of Man" and is quite widely quoted. It comes from As You Like It. The full poem is as follows: All the world's a stage, And all the men and women merely players; They have their exits and their entrances, And one man in his time plays many parts, His acts being seven ages. At first, the infant, Mewling and puking in the nurse's arms. Then the whining schoolboy, with his satchel And shining morning face, creeping like snail Unwillingly to school. And then the lover, Sighing like furnace, with a woeful ballad Made to his mistress' eyebrow. Then a soldie
  3. "......The sixth age shifts Into the lean and slippered pantaloon, With spectacles on nose and pouch on side; His youthful hose, well saved, a world too wide For his shrunk shank, and his big manly voice, Turning again toward childish treble, pipes And whistles in his sound. Last scene of all, That ends this strange eventful history, Is second childishness and mere oblivion, Sans teeth, sans eyes, sans taste, sans everything."
  4. No, no and yes, respectively. (I refer to rest mass, which is what is always meant when speaking of mass nowadays in physics, unless specified to the contrary).
  5. So, "Whiew's the dickhid naow?", as Joss Ackland's character says in Lethal Weapon 2. My acceptance of Fauci's estimated range for the number of deaths in the US seems to be being justified by events. Yours, by contrast, is already too low by a huge margin. I see no way now that the US death toll can be anything less than 80,000, and 100,000 seems quite likely once all the numbers are in. If the lockdowns are taken off too soon, we could see a second wave, to add to that. Readers can draw their own conclusions about whose scientific judgement has proved to be better. As for my politi
  6. Let's try that. Density of basalt ~3, so 40mt would occupy 40/3m³ So we have 4/3 π r³ = 40/3m³, => r³ = 10/π => r = ³√ 3.183 ~1.5m. So by my estimation a 40mt boulder has a radius of 1.5m, so yes a sphere 3m in diameter. And it would need a volume of ice of 400m³, i.e a cube of side ³√400 ~ 7.4m. So yes that indeed checks out.
  7. Let me have a go. Please check my logic and arithmetic. The density of ice is about 0.9. So 1m³ has a mass of 900kg and can take an extra mass of 100kg before it starts to sink. So you need 10m³ of ice per tonne of mass you want it to support. So a 40tonne boulder will need a volume of 400m³. Does that look right?
  8. Haha OK, sorry to muck you about but we do sometimes get schoolkids trying to cheat on their homework on these forums! The answer is about 15% hydrogen by weight. Just to go through the chemistry while we're at it, in case of other readers, a C16 alkane molecule will have 16 carbon atoms, each with atomic mass of 12. The formula I referred to is the one by which the the number of H atoms in an alkane (paraffinic hydrocarbon) with n C atoms is always 2n + 2. So in this case 2x16 +2 =34 hydrogen atoms each of which has a mass of 1. So the mass of the molecule is 16x12 + 34 = 192 + 34 = 22
  9. Looks like homework, so forgive me if I don't just give you an answer. But I don't mind helping a bit if I can. If you take a C16 alkane as typical, you won't be far off. Diesel is a complex mixture of hydrocarbons, mostly in the range C12 - C20, and largely paraffinic (i.e mostly alkanes). So you can get the %wt from that using the well-known formula for alkanes with n carbon atoms. Then all you need to know is the density of diesel, which is a bit over 0.8, say 0.83 kg/l. Do you want to try that and see how you get on?
  10. Just for any non-crank readers there may be (?) , the forgoing post is total ballocks of course. If one calculates the gravitational potential energy gained by a body being separated progressively from another one, e.g. a rocket leaving the Earth, it turns out that, even at infinite separation, the gain in GPE has a finite value. So, if the body possesses a velocity such that its kinetic energy is greater than this GPE value, the body will follow a path that is no longer a closed orbit. It has thus "escaped", even though it continues to feel a force at any finite separation. It turns ou
  11. Not always. In special relativity, p = γmv, where γ = 1/√(1 - (v²/c²) ). But F = dp/dt is always true, whether in Newtonian or relativistic situations. So, dear friend, it is you that needs to learn a bit more.
  12. If you have no idea about that, the chance that you know anything about designing an engine will be infinitesimal.
  13. Another Treaty of Versailles, in fact. Brilliant idea! Let's set up World War 3, why don't we? Those that cannot remember the past are condemned to repeat it.
  14. Sobering animated graphic here, comparing US Covid-19 deaths with other causes of death: https://public.flourish.studio/visualisation/1712761/?fbclid=IwAR3hp7NVELGI98OWUsCtfzlcEFoi5eHJ3SJQHh1P5P7Oax-GHSBuRgF4yAI
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