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  3. TWCP OTD (The Who Cares Puzzle Of The Day) - 15th of February, 2017

TWCP OTD (The Who Cares Puzzle Of The Day) - 15th of February, 2017

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  • Kornfeld Eliyahu PeterK Kornfeld Eliyahu Peter

    WORKS LIKE AN ANT There is a meter long rope tight between two poles. An ant starts running at the speed of 1 cm/s from one end of the rope to the other. At same time the poles are moving back a 1/2 m/s each, stretching the rope (the rope is magical and can be stretched infinitely). Will the ant ever arrive?

    Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

    M Offline
    M Offline
    MarkTJohnson
    wrote on last edited by
    #2

    The poles are moving away from each other at 500 cm/s?

    Kornfeld Eliyahu PeterK J 3 Replies Last reply
    0
    • M MarkTJohnson

      The poles are moving away from each other at 500 cm/s?

      Kornfeld Eliyahu PeterK Offline
      Kornfeld Eliyahu PeterK Offline
      Kornfeld Eliyahu Peter
      wrote on last edited by
      #3

      Yes (that what I meant by 'back')...

      Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

      "It never ceases to amaze me that a spacecraft launched in 1977 can be fixed remotely from Earth." ― Brian Cox

      1 Reply Last reply
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      • M MarkTJohnson

        The poles are moving away from each other at 500 cm/s?

        J Offline
        J Offline
        jeron1
        wrote on last edited by
        #4

        50cm I take it, though for some reason I think he meant .5cm/s.

        "the debugger doesn't tell me anything because this code compiles just fine" - random QA comment "Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst "I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle

        Kornfeld Eliyahu PeterK M 2 Replies Last reply
        0
        • Kornfeld Eliyahu PeterK Kornfeld Eliyahu Peter

          WORKS LIKE AN ANT There is a meter long rope tight between two poles. An ant starts running at the speed of 1 cm/s from one end of the rope to the other. At same time the poles are moving back a 1/2 m/s each, stretching the rope (the rope is magical and can be stretched infinitely). Will the ant ever arrive?

          Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

          J Offline
          J Offline
          Jon McKee
          wrote on last edited by
          #5

          Yes. While the rope is expanding at a total of 1 m/s in both directions, part of that expansion occurs behind the ant. How much at different points on the rope is irrelevant to the solution. The fact that any fraction is expanding behind the ant means that the ant's movement of 1 m/s in a direction gains ground :thumbsup:

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          • J jeron1

            50cm I take it, though for some reason I think he meant .5cm/s.

            "the debugger doesn't tell me anything because this code compiles just fine" - random QA comment "Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst "I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle

            Kornfeld Eliyahu PeterK Offline
            Kornfeld Eliyahu PeterK Offline
            Kornfeld Eliyahu Peter
            wrote on last edited by
            #6

            1/2 m = 50 cm... And I meant that and not 0.5 cm...

            Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

            "It never ceases to amaze me that a spacecraft launched in 1977 can be fixed remotely from Earth." ― Brian Cox

            J 1 Reply Last reply
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            • J jeron1

              50cm I take it, though for some reason I think he meant .5cm/s.

              "the debugger doesn't tell me anything because this code compiles just fine" - random QA comment "Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst "I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle

              M Offline
              M Offline
              MarkTJohnson
              wrote on last edited by
              #7

              Durp! Said cm but gave the number for mm.

              1 Reply Last reply
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              • Kornfeld Eliyahu PeterK Kornfeld Eliyahu Peter

                WORKS LIKE AN ANT There is a meter long rope tight between two poles. An ant starts running at the speed of 1 cm/s from one end of the rope to the other. At same time the poles are moving back a 1/2 m/s each, stretching the rope (the rope is magical and can be stretched infinitely). Will the ant ever arrive?

                Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

                J Offline
                J Offline
                Jon McKee
                wrote on last edited by
                #8

                Yes. The actual speeds are irrelevant to the solution as well. Each time the ant moves, more of the rope expands behind the ant than the previous move and less in front. Eventually when the ant reaches the mid-way point the rope is expanding equally in front and behind. As it moves closer to its destination more and more of the rope is expanding behind the ant. This means that eventually the ant will reach its destination because eventually less rope will expand in front of the ant than the ant can travel which will land the ant at his destination :thumbsup:

                Kornfeld Eliyahu PeterK 1 Reply Last reply
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                • Kornfeld Eliyahu PeterK Kornfeld Eliyahu Peter

                  WORKS LIKE AN ANT There is a meter long rope tight between two poles. An ant starts running at the speed of 1 cm/s from one end of the rope to the other. At same time the poles are moving back a 1/2 m/s each, stretching the rope (the rope is magical and can be stretched infinitely). Will the ant ever arrive?

                  Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

                  N Offline
                  N Offline
                  Nagy Vilmos
                  wrote on last edited by
                  #9

                  I say the ant will certainly arrive. Even if we say the ant is moving after the poles, even though they are separating at the same speed the ant is covering at least a part of the gap. As the gap is getting larger at the same rate as the ant is moving, because the ant is not at the end part of the expansion must be on the part already travelled. So if the gap increases uniformly the extra distance still to travel each second will always be less than 1cm.

                  veni bibi saltavi

                  Kornfeld Eliyahu PeterK 1 Reply Last reply
                  0
                  • J Jon McKee

                    Yes. The actual speeds are irrelevant to the solution as well. Each time the ant moves, more of the rope expands behind the ant than the previous move and less in front. Eventually when the ant reaches the mid-way point the rope is expanding equally in front and behind. As it moves closer to its destination more and more of the rope is expanding behind the ant. This means that eventually the ant will reach its destination because eventually less rope will expand in front of the ant than the ant can travel which will land the ant at his destination :thumbsup:

                    Kornfeld Eliyahu PeterK Offline
                    Kornfeld Eliyahu PeterK Offline
                    Kornfeld Eliyahu Peter
                    wrote on last edited by
                    #10

                    Or in other words - it will be a very-very old ant when getting off the rope...

                    Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

                    "It never ceases to amaze me that a spacecraft launched in 1977 can be fixed remotely from Earth." ― Brian Cox

                    J 1 Reply Last reply
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                    • N Nagy Vilmos

                      I say the ant will certainly arrive. Even if we say the ant is moving after the poles, even though they are separating at the same speed the ant is covering at least a part of the gap. As the gap is getting larger at the same rate as the ant is moving, because the ant is not at the end part of the expansion must be on the part already travelled. So if the gap increases uniformly the extra distance still to travel each second will always be less than 1cm.

                      veni bibi saltavi

                      Kornfeld Eliyahu PeterK Offline
                      Kornfeld Eliyahu PeterK Offline
                      Kornfeld Eliyahu Peter
                      wrote on last edited by
                      #11

                      Can you explain it magyarul?

                      Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

                      "It never ceases to amaze me that a spacecraft launched in 1977 can be fixed remotely from Earth." ― Brian Cox

                      N 1 Reply Last reply
                      0
                      • M MarkTJohnson

                        The poles are moving away from each other at 500 cm/s?

                        Kornfeld Eliyahu PeterK Offline
                        Kornfeld Eliyahu PeterK Offline
                        Kornfeld Eliyahu Peter
                        wrote on last edited by
                        #12

                        My mistake... I somehow stopped at the 'each other' part and cleared the '500 cm/s'... It is away - yes, but only at 50 cm/s... (but that's probably irrelevant anyway)

                        Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

                        "It never ceases to amaze me that a spacecraft launched in 1977 can be fixed remotely from Earth." ― Brian Cox

                        J 1 Reply Last reply
                        0
                        • Kornfeld Eliyahu PeterK Kornfeld Eliyahu Peter

                          1/2 m = 50 cm... And I meant that and not 0.5 cm...

                          Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

                          J Offline
                          J Offline
                          jeron1
                          wrote on last edited by
                          #13

                          That's why I said 'I think' and not 'I correctly think'. :-O :laugh:

                          "the debugger doesn't tell me anything because this code compiles just fine" - random QA comment "Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst "I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle

                          1 Reply Last reply
                          0
                          • Kornfeld Eliyahu PeterK Kornfeld Eliyahu Peter

                            WORKS LIKE AN ANT There is a meter long rope tight between two poles. An ant starts running at the speed of 1 cm/s from one end of the rope to the other. At same time the poles are moving back a 1/2 m/s each, stretching the rope (the rope is magical and can be stretched infinitely). Will the ant ever arrive?

                            Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

                            K Offline
                            K Offline
                            krg
                            wrote on last edited by
                            #14

                            The ant never makes it to the end of the rope. The waveform set up by the flexing of the rope makes the ant dizzy and so he falls off. On his way to the ground he intercepts the path of an arrow that a tortoise has been struggling to run away from for quite some time.

                            Richard DeemingR 1 Reply Last reply
                            0
                            • Kornfeld Eliyahu PeterK Kornfeld Eliyahu Peter

                              Or in other words - it will be a very-very old ant when getting off the rope...

                              Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

                              J Offline
                              J Offline
                              Jon McKee
                              wrote on last edited by
                              #15

                              Approximately 8.547e+35 years if my math is correct :thumbsup:

                              R K U 3 Replies Last reply
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                              • Kornfeld Eliyahu PeterK Kornfeld Eliyahu Peter

                                Can you explain it magyarul?

                                Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

                                N Offline
                                N Offline
                                Nagy Vilmos
                                wrote on last edited by
                                #16

                                Egyszer volt egy kiss hangyat, egyszer nem volt. ;P

                                veni bibi saltavi

                                Richard DeemingR 1 Reply Last reply
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                                • N Nagy Vilmos

                                  Egyszer volt egy kiss hangyat, egyszer nem volt. ;P

                                  veni bibi saltavi

                                  Richard DeemingR Offline
                                  Richard DeemingR Offline
                                  Richard Deeming
                                  wrote on last edited by
                                  #17

                                  Google Translate[^]:

                                  Once there was a kiss ants, not once was

                                  Not sure if it's Google's Hungarian translator that's broken, or your Hungarian. :laugh:


                                  "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

                                  "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

                                  N 1 Reply Last reply
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                                  • K krg

                                    The ant never makes it to the end of the rope. The waveform set up by the flexing of the rope makes the ant dizzy and so he falls off. On his way to the ground he intercepts the path of an arrow that a tortoise has been struggling to run away from for quite some time.

                                    Richard DeemingR Offline
                                    Richard DeemingR Offline
                                    Richard Deeming
                                    wrote on last edited by
                                    #18

                                    If the arrow doesn't get him, the bowl of petunias probably will. :-D


                                    "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

                                    "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

                                    1 Reply Last reply
                                    0
                                    • Richard DeemingR Richard Deeming

                                      Google Translate[^]:

                                      Once there was a kiss ants, not once was

                                      Not sure if it's Google's Hungarian translator that's broken, or your Hungarian. :laugh:


                                      "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

                                      N Offline
                                      N Offline
                                      Nagy Vilmos
                                      wrote on last edited by
                                      #19

                                      I missed an auto correct, kis not kiss. Once there was a little mouse, once there wasn't. Every Hungarian folk tale starts this way.

                                      veni bibi saltavi

                                      1 Reply Last reply
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                                      • J Jon McKee

                                        Approximately 8.547e+35 years if my math is correct :thumbsup:

                                        R Offline
                                        R Offline
                                        Rajesh R Subramanian
                                        wrote on last edited by
                                        #20

                                        Jon McKee wrote:

                                        Approximately 8.547e+35 years if my math is correct

                                        So, that's still younger than @OriginalGriff then.

                                        OriginalGriffO 1 Reply Last reply
                                        0
                                        • Kornfeld Eliyahu PeterK Kornfeld Eliyahu Peter

                                          WORKS LIKE AN ANT There is a meter long rope tight between two poles. An ant starts running at the speed of 1 cm/s from one end of the rope to the other. At same time the poles are moving back a 1/2 m/s each, stretching the rope (the rope is magical and can be stretched infinitely). Will the ant ever arrive?

                                          Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

                                          D Offline
                                          D Offline
                                          dan sh
                                          wrote on last edited by
                                          #21

                                          Yes. The ant does not even need to move. Just stay there. Eventually, destination pole will touch the origin pole due to stretching and Earth being spherical (almost). At that point, just switch lanes. :cool:

                                          "It is easy to decipher extraterrestrial signals after deciphering Javascript and VB6 themselves.", ISanti[^]

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