Physics project help

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  • limitdliability
    Registered User
    • Jan 2002
    • 3
    #1

    Physics project help

    hi,
    i am doing a physics project for my senior year of high school and would like some assistance with something. i would like to attempt to examine the extreme acceleration that the ball undergoes while still in the barrel. but im unsure of an adequate way to do this? did AGD perform a test like this? if so, is there anyway i can simplify their setup? i want a setup to measure the time between the ball begininning to accelerate and when it leaves the barrel. and then i could use a chrono to find the velocity. does that sound right, or am i missing something? I was thinking about using some sort or IR sensor set up, but due to my lack of electronics skills, i dont know how to make something to measure such a small amount of time. would it be accurate enough to begin timing the firing sequence when the trigger is pulled, or could the small amount of time between the trigger pull and the actual firing of the ball throw of the results? do any of you have any ideas? if you have parts lists or some sort of drawing or schematics, im sure i can find enough local help to get it done.
    thank you for your help!

    p.s. i would like to do this with my Angel LED, without any permanent modifications(drilling, tapping, cutting, milling, etc) of any kind. if you think a proper set up would require permanent modifications to the marker, i would be able to use a Tippmann 98C.
    Tags: None
    • Redkey
      Registered User
      • Jan 2002
      • 176
      #2
      my thoughts

      AGD/Tom has posted some plots showing the chamber pressure vs time profile for several markers. Using that information you should be able to determine the acceleration time of a ball. I'm pretty sure these issues have already been discussed here in deep blue.

      If you really wanted to measure the acceleration you would have put a series of optical sensors down the length of the barrel. Then, as the ball accelerated down the barrel it would trip each sensor in sequence giving you a time value for each sensor. Knowing the distance between each sensor and the time each sensor was trip will allow you to calculate/plot the balls velocity as it travels down the barrel.

      If we assume the ball is travelling at 300 ft/sec that means the ball moves about 4 inches per millisecond. You'll have to have some system for making the time measurements that is at least that fast... preferrably 10 times faster for good resolution and discrimination. If you have access to a storage oscilloscope that would be the simplest way to make the measurements. Other methods would be to use a A/D card or a sound card. I mention sound card last because I'm not sure on the electronics needed to condition the input signal. A decent sound card should be able to collect data at 44 KHz which is more than enough for these measurements.

      If you are interested I could continue on and explain how I would build this system. There are others here with much more experience in electronics who would be able to help with the required circuits. The only modifications needed would be to drill a series of thru-holes down the length of a barrel.

      I've been meaning to try this out... I just haven't had the time.

        Comment

        • 314159
          Registered User
          • Nov 2001
          • 555
          #3
          here is the easy way

          buy a really cheap stock barrel

          measure velocity

          cut off 1/2 inch of barrel or whatever length fits your fancy, chrono, and repeat.
          As society and the problems that face it become more and more complex and machines become more and more intelligent, people will let machines make more of their decisions for them, simply because machine-made decisions will bring better results than man-made ones. Eventually a stage may be reached at which the decisions necessary to keep the system running will be so complex that human beings will be incapable of making them intelligently. At that stage the machines will be in effective control. People won't be able to just turn the machines off, because they will be so dependent on them that turning them off would amount to suicide

          sometimes I just freaking hate people. which means the next day I will love them for the sake of balance, but right now I will just concentrate on the hating. Hate hate hate. Blaaaarg! ;)

          turborev - with ai like this, if it controlled any more than a paddle, it would kill you and everyone you care about. ;)

            Comment

            • Redkey
              Registered User
              • Jan 2002
              • 176
              #4
              is that easy or cheesy?

              hahaha... sorry, just kidding.

              Actually it might be a pretty good way to do it, not to mention several orders of magnitude simpler, just make sure that you collect at least 10 datapoints at each barrel length. Another thing to consider is making sure the distance between the muzzle and chrono stays constant as the barrel gets shorter.

              The reason I like the instrumented barrel is that it eliminates any measurement errors associated with an off the shelf chronograph. But, then again, I am an engineering geek.

                Comment

                • limitdliability
                  Registered User
                  • Jan 2002
                  • 3
                  #5
                  well, im currently corresponding with Redkey and learning of his ideas to perform this experiment, but im still very open to any input or additional ideas anyone can input. the more help i have, the better the experiment will be.
                  thanks guys

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