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Even better than the airplane on a treadmill

Discussion in 'General' started by auminer, Nov 13, 2021.

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What is the result?

  1. Smooth ramp wins

    15.7%
  2. Curvy ramp wins

    41.4%
  3. Simultaneous

    18.6%
  4. Hookerz and blow

    24.3%
  1. R Acree

    R Acree Banned

    NERDS!!!!!!!!
     
  2. Smilodon

    Smilodon Wannabe

    (pencils an 'X' in a box) Thank you... "brachistochrone" has been on my WERA board bingo card for 10 long years... Finally! :D
     
  3. auminer

    auminer Renaissance Redneck

  4. Knotcher

    Knotcher Well-Known Member

    The ramp on the left looked liked it had upwards elevation change to me until i looked at the vidjayo.
     
  5. Mongo

    Mongo Administrator

    Curvy. Higher acceleration from steep more than offsets the flats.
     
  6. Sabre699

    Sabre699 Wait...hold my beer.

    Shit...anyone who's skied black diamonds or out of bounds could have told ya.
     
    Once a Wanker.. likes this.
  7. Nick_OMC

    Nick_OMC Will crash your bike

    Can I vote for Durrani wheels? :crackup:
     
  8. auminer

    auminer Renaissance Redneck

    OK... another one for you Einsteins. No reason to make a new thread.

    [​IMG]


    An old car has to go up & over a hill.

    It's a clapped out POS, so it can only manage 15 miles an hour for the climb. However, it can skedaddle along pretty well on the downslope. The uphill ascent is one mile in length, as is the downslope.

    How fast must the car average on the downslope to average 30 miles an hour for the two mile drive up & over the hill?
    q398AqtTEL8
     
  9. brex

    brex Well-Known Member

    Not possible.
     
  10. tgold

    tgold Well-Known Member

    Tree fiddy
     
  11. motoracer1100

    motoracer1100 Well-Known Member

    1) if it only goes 15 MPH uphill , it should be lit on fire and call insurance company.

    2) on downslope, it must travel 15 MPH over the legal speed limit to accomplish this task .

    3) the speed of POS car is dependent on the torque of the lug nuts holding on wheels .

    4) no one should ever drive a POS car ... either up or downhill .

    5) what kind of Michelin tires does this car have ?

    6) what Southern state is this car registered in ?

    7) top speed of car is determined by it’s exterior color ....
     
  12. Motofun352

    Motofun352 Well-Known Member

    Enter the worm hole at the crest and simultaneously appear at the bottom...
     
    Monsterdood and auminer like this.
  13. SuddenBraking

    SuddenBraking The Iron Price

    :stupid:

    Had to think about that one for a minute; more of a trick question than anything else.
     
  14. R1M370

    R1M370 Dr. P Ness

    45 mph down hill right?

    If you did 15 in the first mile and 45 in the second mile you'd have an average of 30mph over 2 miles.
     
  15. SuddenBraking

    SuddenBraking The Iron Price

    Convert that speed to time.

    To average 30mph over 2 miles means you cover that distance in 4 minutes.

    To cover the first leg at 1 mile in 15 minutes takes 4 minutes*.

    *This is assuming "average" is the mean and not mode or median.
     
    R1M370 likes this.
  16. dsapsis

    dsapsis El Jefe de los Monos

    There are three classical Pythagorean means: arithmetic, harmonic, and geometric (think standard error assessment of variance both above and below a value). When averaging velocity (rates, or more generally, reciprocals), one uses the harmonic mean. The mode isn't an average at all, and median is based on the cumulative frequency distribution representing the 50th% quantile of observations.

    About 30 years, my major professor and I discovered a bug in the widely used software used to predict wildland fire spread under a 2-fuel model case -- it used the arithmetic mean function (like R1M) mistakenly, despite the model being elegant (it is still in wide use today, albeit with improved interface and other enhancements) and the software written by smart people. Sometimes small things get overlooked when doing larger projects.

    Where's that poindexter smile, anyway?
     
    Once a Wanker.. likes this.
  17. Once a Wanker..

    Once a Wanker.. Always a Wanker!

    You'd enjoy a conversation with my daughter, if she wasn't so busy now. Working hard to finish up her thesis for her doctorate in bio-statistics at Vanderbilt, by the end of the year.
     
  18. dsapsis

    dsapsis El Jefe de los Monos

    Good for her -- lots of great work opportunities in that field. Of course, there are lots of Beebsters that would tell her those epi models that run on biostat engines are FOS. Shit, I got schooled on wildfire by a welder. :beer:
     
    Once a Wanker.. likes this.
  19. OldGuyOnBlu

    OldGuyOnBlu Well-Known Member

    There always has to be one really smart guy -- A math nerd -- to F up a thread for us more challenged.
     
  20. mattys281-2

    mattys281-2 Well-Known Member

    No the question was about rate over a specified distance, didn’t mention elapsed time. Your rate of travel can still average out to anything, depending on what it was over the second half.

    what was really fun in calc class was when we tried to get rates at certain pints in the position graph and you had to start to consider rate at small slices of the function. Can’t remember the name of that formula, but thank God for TI graphing calculators!
     

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