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Linear Frequency?

  1. Jun 22, 2010 #1
    How would you go about determening a linear frequency, compared to that of a rotational frequency. For instance, determining the frequency of a piston in cylcles/second?

    I would assume velocity has to be involved, and the length of the stroke. How is velocity put into play, is it constant, or does it go in one direction, stop at 0 velocity, and then immediatly speed back up. Thats what it would do in the engine, but how do you account for this?

    Help please!
     
  2. jcsd
  3. Jun 22, 2010 #2

    Lok

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    A lfrequency is just that, the number of cycles ( oscilations, rotations or more complex motions) per second. If a piston starts at a position, then moves and comes back again to it's starting position then it completed a cycle.

    If you consider the fact that piston stokes can be mechanically converted to rotations then it is very easy to understand the concept. Like in a crankshaft and connecting rod, where an engine has the same frecquency for the piston as for the crankshaft.
     
  4. Jun 23, 2010 #3
    Ah hah, thinking too complicated gets the best of me again. Essentially the piston would have the same frequency as the RPM's that the engine is undergoing correct?
     
  5. Jun 23, 2010 #4

    Lok

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    Yes, the engines RPM is the number of cycles(rotations) / minute of the crankshaft, which is the same RPM ( although no rotation this time) of the piston. Speed does not matter as for the same frequency to pistons can travel 2 different paths (one longer one shorter) and still have the same rpm.
     
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