Recent content by mjc123

  1. M

    Undergrad Exoplanet, HD 137010 b and it's star, HD 137010

    Remember to account for the different radius; g = GM/r2. So g x 1.19/1.062 = 10.39 m/s2
  2. M

    Jokes and a language: how does it work?

    https://www.unz.com/PDF/PERIODICAL/Encounter-1983nov/97-98/
  3. M

    Jokes and a language: how does it work?

    In the 1980s the British left-wing miners' union leader Arthur Scargill visited the Soviet Union and made a speech in which he referred to "Ronald Ray-gun" and Margaret Thatcher as "the plutonium blonde". The apparatchiks were bemused because of course the puns didn't translate into Russian...
  4. M

    Random Thoughts 7

    "Evening of Clairvoyance: Cancelled due to unforeseen circumstances."
  5. M

    Collection of Lame Jokes

    Don't try it! https://en.wikipedia.org/wiki/Cat_bin_woman_incident
  6. M

    Why do octets lead to a stable configuration?

    They don't intrinsically. A sodium atom with a single electron in the 3rd shell is more stable than a sodium ion (with a closed shell configuration) and a free electron. Why then does sodium form ionic compounds containing the Na+ ion? You have to consider the total energetics of the compound...
  7. M

    Random Thoughts 7

    Yes. I remember when the company was in the news for boring car-industry reasons.
  8. M

    Undergrad Conditional variance and total variance

    To simplify, imagine X is drawn randomly with 50% probability from either of 2 distributions N(μ1,σ2) and N(μ2,σ2), with μ1 - μ2 >> σ. Do you imagine the variance of X will be equal to the mean of the two separate variances, i.e. σ2? It will obviously depend on the difference between the means...
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    Collection of Lame Jokes

    Or in England.
  10. M

    High School How much lower would a sheep be expected to jump if on a steep upward slope?

    You misunderstand the question. 1 m is a measure of height, not steepness. The question is, over what horizontal distance does the height change by 1 m?
  11. M

    Collection of Lame Jokes

    Could have called it a "lift".
  12. M

    Magnitude of buoyant force in fluids of different densities

    Remember: a floating body displaces its own weight of fluid; A submerged body displaces its own volume of fluid. Whether it floats or sinks depends on its own density relative to the fluid.
  13. M

    Two-layer dielectric, four-capacitor model vs three-capacitor model

    But I don't accept your premise. You assert that the top plate's charge distribution doesn't change, therefore the electric field doesn't change. Why? I say that the electric field changes, depending on what's between the plates, and therefore the charge density will change too. The key point is...
  14. M

    Two-layer dielectric, four-capacitor model vs three-capacitor model

    I think you are right. The book solution implicitly assumes that the voltage at the bottom of slab 1 is constant across the width, which is not the case. You have to treat it as two series combinations in parallel.