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    has anyone got any M3 tips? specifically with simple harmonic motion

    when I'm asked to 'prove that this moves with SHM', I understand you always find an expression for acceleration = -k(displacement), but when it comes to vertical strings, horizontal springs, springs, etc... I find it hard to know what equation to form to reach this stage

    does anyone have a rule or something in short which gives this?


    EDIT:

    to make my point clearer, with vertical springs you usually do T-mg=-a, so do you just use f=ma in all of them?
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    Zacken
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    actually for mechanics ... A Slice of Pi
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    (Original post by Ummah dawn)
    has anyone got any M3 tips? specifically with simple harmonic motion

    when I'm asked to 'prove that this moves with SHM', I understand you always find an expression for acceleration = -k(displacement), but when it comes to vertical strings, horizontal springs, springs, etc... I find it hard to know what equation to form to reach this stage

    does anyone have a rule or something in short which gives this?
    You should always call your origin point the equilibrium point, so if it's on a string/spring, etc... always find the equilibirum then consider the extension from there. Call your extension x then resolve forces in the direction of x increasing so that you can use Newton's second law: \sum F_i = m\ddot{x}, you should find all constant terms cancel out and you're left with an equation of the form \ddot{x} = -\omega^2 x as required.
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    okay thanks guys ill have a quick look at some more qs
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    (Original post by Ummah dawn)
    has anyone got any M3 tips? specifically with simple harmonic motion

    when I'm asked to 'prove that this moves with SHM', I understand you always find an expression for acceleration = -k(displacement), but when it comes to vertical strings, horizontal springs, springs, etc... I find it hard to know what equation to form to reach this stage

    does anyone have a rule or something in short which gives this?


    EDIT:

    to make my point clearer, with vertical springs you usually do T-mg=-a, so do you just use f=ma in all of them?
    To add to what Zacken said, you should be finding your tensions using Hooke's Law in terms of x and you will notice that the terms that are not in terms of x will cancel out quite nicely.
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    (Original post by TeeEm)
    actually for mechanics ... A Slice of Pi
    Looks like I'm a bit late but thanks for the recommendation
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    (Original post by A Slice of Pi)
    Looks like I'm a bit late but thanks for the recommendation
    my pleasure
 
 
 
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