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Nothing to do with programming : question for physicits

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  • C Christopher Duncan

    Saaaay, no fair. Aren't you supposed to figure out your homework assignments for yourself? :-) Chistopher Duncan Author - The Career Programmer: Guerilla Tactics for an Imperfect World (Apress)

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    Weiye Chen
    wrote on last edited by
    #3

    LOL :laugh: I agree this looks like a homework assignment ;P Weiye, Chen When pursuing your dreams, don't forget to enjoy your life...

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    • J Jerome Conus

      Hi ! I have a question about physics, and I though maybe someone from the CP community might be able to help me : Let's imagine a train, following a railway. The train has a speed S and arrives with this speed in a turn (of a given radius R). If the mass of the train is important, let's say it's mass is M. How can I calculate at which speed, the train will be too fast and will leave the rail ???? And, maybe the train won't leave the rail immediately at the beginning of the turn, but, let's say, somewhere in the middle of the turn. How can I calculate this position where the train will leave the rail ? Thank you !!! Jerome

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      Paul Watson
      wrote on last edited by
      #4

      Wait... my divine knowledge of celestial parephenalia tell me that... wait... wait... wait... this is a homework question! If it is not then my apologies, but it reeks of it and is no better than a programming homework question. And I don't know the answer. Surely you need more info though. Rail depth, depth of groove in train wheels, is Fat Bastard on the train, location of Biggs at the time etc. etc.

      Paul Watson
      Bluegrass
      Cape Town, South Africa

      Macbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Want a job?

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      • J Jerome Conus

        Hi ! I have a question about physics, and I though maybe someone from the CP community might be able to help me : Let's imagine a train, following a railway. The train has a speed S and arrives with this speed in a turn (of a given radius R). If the mass of the train is important, let's say it's mass is M. How can I calculate at which speed, the train will be too fast and will leave the rail ???? And, maybe the train won't leave the rail immediately at the beginning of the turn, but, let's say, somewhere in the middle of the turn. How can I calculate this position where the train will leave the rail ? Thank you !!! Jerome

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        Jorgen Sigvardsson
        wrote on last edited by
        #5

        Jerome Conus wrote: How can I calculate at which speed, the train will be too fast and will leave the rail ???? You'll have to calculate the artificial gravity of the train due to its speed through the corner. You'll find that formula in your physics book. Then combine that with the gravity pull by earth to get the total force vector affecting the train. Simple picture of train and forces:

        +---------+
        

        Fh | |
        <---+----x |
        | | |
        dy | | |
        +----+----+
        dx |
        v Fv

        The above picture is a simplification of the train. You've got two major forces: Fh and Fv. Fh, Force horizontal, is the artificial gravity due to the speed/corner. Fv is the earths gravity pull. The train will fall when Fh * dy > Fv * dx, where dy and dx are horizontal and vertical distances respectively, from the outmost train wheel to the mass center of the train. So basically, when the momentum is stronger counter clockwise than clockwise, the train will fall over. -- I'm coming out of the closet: I :love: VB

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        • P Paul Watson

          Wait... my divine knowledge of celestial parephenalia tell me that... wait... wait... wait... this is a homework question! If it is not then my apologies, but it reeks of it and is no better than a programming homework question. And I don't know the answer. Surely you need more info though. Rail depth, depth of groove in train wheels, is Fat Bastard on the train, location of Biggs at the time etc. etc.

          Paul Watson
          Bluegrass
          Cape Town, South Africa

          Macbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Want a job?

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          Roger Allen
          wrote on last edited by
          #6

          Paul Watson wrote: location of Biggs at the time and how much money is on the train. :-D Roger Allen Sonork 100.10016 Were you different as a kid? Did you ever say "Ooohhh, shiny red" even once? - Paul Watson 11-February-2003

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          • J Jerome Conus

            Hi ! I have a question about physics, and I though maybe someone from the CP community might be able to help me : Let's imagine a train, following a railway. The train has a speed S and arrives with this speed in a turn (of a given radius R). If the mass of the train is important, let's say it's mass is M. How can I calculate at which speed, the train will be too fast and will leave the rail ???? And, maybe the train won't leave the rail immediately at the beginning of the turn, but, let's say, somewhere in the middle of the turn. How can I calculate this position where the train will leave the rail ? Thank you !!! Jerome

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            Giles
            wrote on last edited by
            #7

            For one thing your going to need to know the centre of gravity of the train. Also are you assuming that if one carrige goes the others go, which in real life would not be the case? This can be easily investigated by looking at a cross section of a train. First look at this from the point of view of a train at rest, where someone is trying to push it over by hand - not likey either. You need to know the vertical acceleration (gravity - not hard) and the lateral force ( this will later come from going around the corner at speed), along with the centre of gravity. You can work out the horizontal force required to tip the train over at rest, by combining the two force vectors until they are outside the wheel base - at which point the train will start to tip. The acceleration from going around a bend is (me thinks - been a while) acceleration = angular velocity * radius Once the acceleration from going around the bend surpases the at rest push over acceleration then your there. And if that make sense then god help you. :laugh: Quote from a clever bloke : "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." - Albert Einstein

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            • J Jerome Conus

              Hi ! I have a question about physics, and I though maybe someone from the CP community might be able to help me : Let's imagine a train, following a railway. The train has a speed S and arrives with this speed in a turn (of a given radius R). If the mass of the train is important, let's say it's mass is M. How can I calculate at which speed, the train will be too fast and will leave the rail ???? And, maybe the train won't leave the rail immediately at the beginning of the turn, but, let's say, somewhere in the middle of the turn. How can I calculate this position where the train will leave the rail ? Thank you !!! Jerome

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              Kastellanos Nikos
              wrote on last edited by
              #8

              What is the height of each vagon (actually where is the mass center) and what is the distance between the 2 rails? I think a vagon leaves the rail when it slope to the point that it's mass center goes outside the rails. :) One idea is to devide the vector of the speed into 2 perpendicular vectors, one pointing to the direction of the rails. The other vector whould be the power that 'push' the vagon outside the rail. - - - - - - - - - - - - - - - - - - Memory leaks is the price we pay \0 01234567890123456789012345678901234

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              • R Roger Allen

                Paul Watson wrote: location of Biggs at the time and how much money is on the train. :-D Roger Allen Sonork 100.10016 Were you different as a kid? Did you ever say "Ooohhh, shiny red" even once? - Paul Watson 11-February-2003

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                Paul Watson
                wrote on last edited by
                #9

                Roger Allen wrote: and how much money is on the train Eeeeeeeeexactly. :-D

                Paul Watson
                Bluegrass
                Cape Town, South Africa

                Macbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Want a job?

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                • P Paul Watson

                  Wait... my divine knowledge of celestial parephenalia tell me that... wait... wait... wait... this is a homework question! If it is not then my apologies, but it reeks of it and is no better than a programming homework question. And I don't know the answer. Surely you need more info though. Rail depth, depth of groove in train wheels, is Fat Bastard on the train, location of Biggs at the time etc. etc.

                  Paul Watson
                  Bluegrass
                  Cape Town, South Africa

                  Macbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Want a job?

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                  Christopher Duncan
                  wrote on last edited by
                  #10

                  Paul Watson wrote: Surely you need more info though. Rail depth, depth of groove in train wheels, is Fat Bastard on the train, location of Biggs at the time etc. etc. Along with the average width of a horse's posterior as a constant, for validating the proper width of rail placement... Chistopher Duncan Author - The Career Programmer: Guerilla Tactics for an Imperfect World (Apress)

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                  • K Kastellanos Nikos

                    What is the height of each vagon (actually where is the mass center) and what is the distance between the 2 rails? I think a vagon leaves the rail when it slope to the point that it's mass center goes outside the rails. :) One idea is to devide the vector of the speed into 2 perpendicular vectors, one pointing to the direction of the rails. The other vector whould be the power that 'push' the vagon outside the rail. - - - - - - - - - - - - - - - - - - Memory leaks is the price we pay \0 01234567890123456789012345678901234

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                    Christopher Duncan
                    wrote on last edited by
                    #11

                    Kastellanos Nikos wrote: What is the height of each vagon And how bad is the poetry? Oh. Sorry. Thought that was Vogon... Chistopher Duncan Author - The Career Programmer: Guerilla Tactics for an Imperfect World (Apress)

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                    • W Weiye Chen

                      LOL :laugh: I agree this looks like a homework assignment ;P Weiye, Chen When pursuing your dreams, don't forget to enjoy your life...

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                      Jerome Conus
                      wrote on last edited by
                      #12

                      Weiye Chen wrote: looks like a homework assignment Come on guys....I finished my studies 7 years ago, this has nothing to do with homework.... But I agree that if, by that time, I would have be keener at doing my homeworks, I wouldn't be posting this question today !!! ;-) Jerome

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                      • J Jerome Conus

                        Hi ! I have a question about physics, and I though maybe someone from the CP community might be able to help me : Let's imagine a train, following a railway. The train has a speed S and arrives with this speed in a turn (of a given radius R). If the mass of the train is important, let's say it's mass is M. How can I calculate at which speed, the train will be too fast and will leave the rail ???? And, maybe the train won't leave the rail immediately at the beginning of the turn, but, let's say, somewhere in the middle of the turn. How can I calculate this position where the train will leave the rail ? Thank you !!! Jerome

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                        benjymous
                        wrote on last edited by
                        #13

                        What? A physics question in the lounge?!? You'd be better off in the Visual Physics++ forum, or perhaps the Physics.NET forum ;P -- Help me! I'm turning into a grapefruit!

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                        • B benjymous

                          What? A physics question in the lounge?!? You'd be better off in the Visual Physics++ forum, or perhaps the Physics.NET forum ;P -- Help me! I'm turning into a grapefruit!

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                          Paul Watson
                          wrote on last edited by
                          #14

                          benjymous wrote: Physics.NET forum A train derailment hypothesis is not safe code so would need the appropriate markings in .NET. VP++ is probably the better language.

                          Paul Watson
                          Bluegrass
                          Cape Town, South Africa

                          Macbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Want a job?

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                          • P Paul Watson

                            Wait... my divine knowledge of celestial parephenalia tell me that... wait... wait... wait... this is a homework question! If it is not then my apologies, but it reeks of it and is no better than a programming homework question. And I don't know the answer. Surely you need more info though. Rail depth, depth of groove in train wheels, is Fat Bastard on the train, location of Biggs at the time etc. etc.

                            Paul Watson
                            Bluegrass
                            Cape Town, South Africa

                            Macbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Want a job?

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                            Jerome Conus
                            wrote on last edited by
                            #15

                            Paul Watson wrote: Wait... my divine knowledge of celestial parephenalia tell me that... wait... wait... wait... this is a homework question! If it is not then my apologies, but it reeks of it and is no better than a programming homework question. I admit that my question smelled like homework, but after a quick look at my profile you would have notice that studies are now several years behind me :-) But thank you for pointing out that my question was lacking important informations about Fat Bastard and Biggs ! ;-) Jerome

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                            • P Paul Watson

                              benjymous wrote: Physics.NET forum A train derailment hypothesis is not safe code so would need the appropriate markings in .NET. VP++ is probably the better language.

                              Paul Watson
                              Bluegrass
                              Cape Town, South Africa

                              Macbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Want a job?

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                              benjymous
                              wrote on last edited by
                              #16

                              And of course Visual High School Physics is worth avoiding like the plague, as it teaches you rubbish like the atom being the smallest datatype. It's perfectly good as a learning language though -- Help me! I'm turning into a grapefruit!

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                              • J Jerome Conus

                                Paul Watson wrote: Wait... my divine knowledge of celestial parephenalia tell me that... wait... wait... wait... this is a homework question! If it is not then my apologies, but it reeks of it and is no better than a programming homework question. I admit that my question smelled like homework, but after a quick look at my profile you would have notice that studies are now several years behind me :-) But thank you for pointing out that my question was lacking important informations about Fat Bastard and Biggs ! ;-) Jerome

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                                Paul Watson
                                wrote on last edited by
                                #17

                                Jerome Conus wrote: I admit that my question smelled like homework, but after a quick look at my profile you would have notice that studies are now several years behind me But thank you for pointing out that my question was lacking important informations about Fat Bastard and Biggs Jeeesh, giving me something to work with here. Now I have to post a stupid reply admiting I can't figure out how to argue with you any further. Throw me a frikin bone man! :rolleyes: Oh, and we should never stop learning. Plenty of guys here in their 50s who are doing part time course at Uni.

                                Paul Watson
                                Bluegrass
                                Cape Town, South Africa

                                Macbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Want a job?

                                1 Reply Last reply
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                                • B benjymous

                                  And of course Visual High School Physics is worth avoiding like the plague, as it teaches you rubbish like the atom being the smallest datatype. It's perfectly good as a learning language though -- Help me! I'm turning into a grapefruit!

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                                  Jorgen Sigvardsson
                                  wrote on last edited by
                                  #18

                                  benjymous wrote: as it teaches you rubbish like the atom being the smallest datatype. Well, it doesn't get any better at University level either. Then you're taught that strings are the smallest datatypes! :omg: Sheesh. I wonder if I get a Nobel prize if I do some research on char? :cool: -- I'm coming out of the closet: I :love: VB

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                                  • C Christopher Duncan

                                    Paul Watson wrote: Surely you need more info though. Rail depth, depth of groove in train wheels, is Fat Bastard on the train, location of Biggs at the time etc. etc. Along with the average width of a horse's posterior as a constant, for validating the proper width of rail placement... Chistopher Duncan Author - The Career Programmer: Guerilla Tactics for an Imperfect World (Apress)

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                                    Jerome Conus
                                    wrote on last edited by
                                    #19

                                    Christopher Duncan wrote: Along with the average width of a horse's posterior as a constant, for validating the proper width of rail placement... No kidding : the width of a horse is VERY important !!! :-) Did you know that the width of a horse's posterior is the origin of the size of the booster rockets of the Space Shuttle ??? In english : http://info.mountains.net.au/rail/horse-ass.htm[^] For french speakers : http://lwdr.free.fr/disjonctes.html#L'ESPACEMENT%20D'UN%20CUL%20DE%20CHEVAL[^] Jerome

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                                    • C Christopher Duncan

                                      Kastellanos Nikos wrote: What is the height of each vagon And how bad is the poetry? Oh. Sorry. Thought that was Vogon... Chistopher Duncan Author - The Career Programmer: Guerilla Tactics for an Imperfect World (Apress)

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                                      Kastellanos Nikos
                                      wrote on last edited by
                                      #20

                                      Christopher Duncan wrote: And how bad is the poetry? Oh. Sorry. Thought that was Vogon... uh, those greek QCERTY-type keyboards. They make you do all sort of strange mistakes... ;P - - - - - - - - - - - - - - - - - - Memory leaks is the price we pay \0 01234567890123456789012345678901234

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                                      • K Kastellanos Nikos

                                        Christopher Duncan wrote: And how bad is the poetry? Oh. Sorry. Thought that was Vogon... uh, those greek QCERTY-type keyboards. They make you do all sort of strange mistakes... ;P - - - - - - - - - - - - - - - - - - Memory leaks is the price we pay \0 01234567890123456789012345678901234

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                                        Andreas Saurwein
                                        wrote on last edited by
                                        #21

                                        Kastellanos Nikos wrote: uh, those greek QCERTY-type keyboards. So you are programming in W++, right? :)


                                        powerful binary resource reuse - another word for "no sources, you are stuck with a pain-in-the-a## COM component"

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                                        • J Jerome Conus

                                          Hi ! I have a question about physics, and I though maybe someone from the CP community might be able to help me : Let's imagine a train, following a railway. The train has a speed S and arrives with this speed in a turn (of a given radius R). If the mass of the train is important, let's say it's mass is M. How can I calculate at which speed, the train will be too fast and will leave the rail ???? And, maybe the train won't leave the rail immediately at the beginning of the turn, but, let's say, somewhere in the middle of the turn. How can I calculate this position where the train will leave the rail ? Thank you !!! Jerome

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                                          Lost User
                                          wrote on last edited by
                                          #22

                                          With a bit of work you can probably get it down to 50 variables: Centre of gravity of train Camber of rails Amount of oil/grease/dirt on rails etc..... Elaine :rolleyes: The tigress is here :-D

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