Recent content by JR Jonsson

  1. J

    Can Vacuum-Induced Evaporation Explain the Loss of Water in Comets?

    Old thred but anyway: A comet may illustrate this. It obviously contains water for a long time, but some evaporate when hit by some sunschine.
  2. J

    Can I Measure Total Pressure with a Thin Pipe Instead of a Pitot Tube?

    That's right, take care of the instruments.
  3. J

    XKCD's "Climate Change Timeline" | See History's Impact

    Cool timeline. Scary comic. Let's continue whith netmeeting as a start.
  4. J

    Can I Measure Total Pressure with a Thin Pipe Instead of a Pitot Tube?

    Normaly there is no flow in a pitot tube, so the smooth schould be in the opening of the tube. It's just a question of accurasy in the messure. Is it really the total pressure you want ? A typical pitot tube are used to result in the dynamik pressure whitch gives you speed / flow of the fluid...
  5. J

    Unit conventions (SI versus others)

    You make me confused. For me it is physics to calculate f.ex. the heat loss in a building, equippment as pipes, pump's, radiators and heatpump needed to keep the house warm. Compare the calculations needed whith SI resp. Imperial units; is there no difference ?
  6. J

    Unit conventions (SI versus others)

    I'm sorry if i expressed myself badly. Offcourse you in this forum understand SI and it's benefits. That is why I am taking part in here. What i meant was the uncovinience with the imperial units ( or what it's named) when dealing whith US technical matters, and US has some influence on the...
  7. J

    Why is the Velocity equal to joules per kilogram?

    The area of a rektangel is for ex. 2 m • 4 m = 8 m^2 The area of a triangel is for ex. 2 m • 4 m /2 = 4 m^2 Make a diagram for velosity and time in the case of free fall and you get a triangel. The area of this triangel is for the first second 1 s • 10/2 m/s = 5 m ( gravity 10 m/s^2, or 10...
  8. J

    Unit conventions (SI versus others)

    I know SI is in use in U.S as well as other units are common everywhere As a step on the way you can use both old units and SI (as for "cal" and "J" on all food declarations in sweden) My point is that physics is hard enough to understand without unit conversions. I had a student some years back...
  9. J

    Vacuum or pressure to move spaghetti through a hole

    Hello all friends of science I am new in this nice forum and not so good in math, but i would appreciate a response on my view in this matter even if its late in this thread. I think of the aspect "energy= pressure * volume" If there is a different potential/energy (here inside the mouth versus...
  10. J

    Why is (not) the resulting unit of this equation rad/s ?

    I think you are clever. Obviously there is an error in the conventions when energy equals torque. Torque should have the unit Nm/rad. That could be acceptable if radius defines as m/rad
  11. J

    Unit conventions (SI versus others)

    Can anyone explain to me how it comes that US not have accepted the use of SI ? Do you not understand the benefits ? Would it not be more effective if the new generation of students could concentrate on understanding fundamental physics relations rather than struggle whith old-fashioned and...
  12. J

    I DDWFTTW: Looking for the least confusing explanation

    As a kid i played with a spool and was fachinated abaut the fakt that the spool came closer too me even when it meant that the thred was winded up on the spool. There you have the force aspect in this matter. Imagine you are in a train with no floor. Put down a wheel, driven by the moving...
Back
Top