Recent content by Halc

  1. Halc

    Stick leaning on the wall, find the acceleration from the initial position

    No, there is no conservation here. The system isn't closed since unbalanced torque and linear forces are supplied by the wall (at B) and the ground where the rolling takes place.
  2. Halc

    Stick leaning on the wall, find the acceleration from the initial position

    A (presumed solid) cylinder with a known mass and radius has an expressible moment of inertia. Likewise a (presumed uniform density) stick with known length and mass. Eww, that's a problem since length of stick is not provided. Is the answer not dependent on stick length then? A long stick will...
  3. Halc

    Stick leaning on the wall, find the acceleration from the initial position

    Admittedly not a trivial problem. The horizontal force exerted on the cylinder by the stick is not equal to the force exerted on the stick by the wall. The stick gains both momentum (west) and angular momentum (clockwise) as it falls, both reducing the acceleration of the cylinder from the much...
  4. Halc

    Stick leaning on the wall, find the acceleration from the initial position

    Mutually contradictory statements. I presume there is static friction between the cylinder and the surface upon which it rolls, else it would just start sliding, not rolling. You have some text, but have not expressed the component forces acting on/by the stick at points A and B, and for that...
  5. Halc

    B Object falling through highly compressed air question

    Indeed, I forgot the square root part. And I was looking right at it. The formula you quote (and which I should have quoted) still doesn't take buoyancy into account, as described in my post. Terminal velocity of a helium balloon would be downward, not upward, according to that formula.
  6. Halc

    B Object falling through highly compressed air question

    Terminal velocity is ((2mg)/(ρAC)) mass, gravity/acceleration, ρ density of fluid, Area and C=drag coefficient So 6000 psi is about 400 times the density of atmosphere at sea level, so the anvil falls at around 1/400th the speed. This formula doesn't take into account the buoyancy of the...
  7. Halc

    I Time dilation due to gravitation forces and velocity

    A ship cannot travel at light speed relative to anything. So say it just goes real fast. Yes, more time will have elapsed on Earth due to the trip out and back. The ship has no single inertial frame of reference, so 'the ship's frame of reference' is an accelerated one, and yes, this is true of...
  8. Halc

    B Speed of light versus wavelength

    If enough sugar and a slow enough car, it very much does mean that in the frame of the road, he literally travels a path twice as long and twice as fast as the sleeping kid, which is why the kids in the car analogy is terrible. jbriggs444 expressed it better.
  9. Halc

    Collection of Lame Jokes

    Now 10443, that one was fecesious
  10. Halc

    I Violation of Special Relativity Principle (thought experiment)

    If you mean a large number of clocks all stationary relative to some inertial frame and synced in that frame, then yes, an observer moving relative to that frame and looking at those clocks go by like frames in a movie would see them tick fast by a factor of gamma. He could also watch the...
  11. Halc

    B Untraditional Space Travel

    Infinite energy would entail infinite mass, which would prevent anything from getting into orbit at all. Perhaps you mean just free energy, in which case you'd have to work out exactly what isn't free and find a solution that makes the most efficient use of those more limited resources.
  12. Halc

    B Untraditional Space Travel

    Any trajectory you put it in will come from the atmosphere. If it isn't moving at escape velocity at the time it exits the atmosphere, it will come back and go through re-entry regardless of trajectory. It cannot reach LEO unassisted.
  13. Halc

    I Question about n rotating parallel cylinders

    See? That's a snowman shape, except rotated on its side. Extend it in 3D and it's a snowmanular cylinder. Sheesh, you guys need to lighten up. Oh. That wasn't clear from the OP.
  14. Halc

    I Question about n rotating parallel cylinders

    If there are n identical cylinders and each has angular momentum of p, then the total angular momentum (be they apart or brought together) is n*p. That or external torque was applied, but you don't indicate that. So if two of them are brought together, they'll form a sort of spinning...
  15. Halc

    Collection of Lame Jokes

    Help me! I am trapped in a Haiku factory Save me before they... I got your message I have found my way inside Oh my god, what the ...
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