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Homework Help: Resonance need explanation (No maths)

  1. Nov 6, 2006 #1
    I know that when the applied frequency on a mass is equal to the natural frequency, the mass resonates. It has a great amplitude as a result of this.

    But I don't know how somethings affect the resonant frequency.

    Like for a mass-spring system.
    1) What effect would increasing the mass have on the resonant frequency?
    2) What effect would stiffer springs have on a resonant frequency?

    Also if a vehicle that is lightly damped passing over a bump at a certain speed, its chassis
    bounced violently.
    I know this is because the resonant frequency is equal to the applied frequency.
    Does constructive interference play a part for the huge increase in amplitude?

    3) What effect would it have on the resonant frequency of the vehicle is traveling at a different speed?
    4) What effect would it have on the resonant frequency if more passengers were in the car?

    Thanks, I just need some explanations so I can understand this.
  2. jcsd
  3. Nov 6, 2006 #2


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    Staff: Mentor

    Well, what do you think in the case of -1- and -2-? Think about a guitar string. What happens to the tone of the plucked string as you tighten the string? That should help you with -2-. Why do they use heavier strings for the lower note strings? That should help you with -1-. For the others, what does your textbook say about constructive interference?
  4. Nov 6, 2006 #3
    I don't know anything about guitars but,

    I think if the string was tightened it would give a high note so does this make the resonant frequency higher because the frequency of the string would be greater?

    Heavier strings give lower notes so does this mean it will shift the resonant frequency lower?

    The textbook which has these questions don't provide any answers.
    It also does not contain any information about constructive and destructive interference. I remember the constructive interference from experiments done in class. Something about waves reinforcing each other and canceling when destructive interference happens.
    I just had a thought if these played a part in resonance.

    Also if the resonant frequency is increased/decreased does that make it harder/easier for the applied frequency to make it resonate? Or it doesn't affect it at all?
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