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    Hi I was doing my first past paper and I got stuck on this question and no matter how much I try i cant seem to understand how they arrive at the answer.

    The question is 4bi on
    http://store.aqa.org.uk/qual/gce/pdf...W-QP-JAN10.PDF

    And the markscheme is here
    http://store.aqa.org.uk/qual/gce/pdf...W-MS-JAN10.PDF

    How am I supposed to know how to draw this. Surely I can draw it however I want as long I put a node where they have told me :confused:

    Thanks
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    (Original post by user1-4)
    Hi I was doing my first past paper and I got stuck on this question and no matter how much I try i cant seem to understand how they arrive at the answer.

    The question is 4bi on
    http://store.aqa.org.uk/qual/gce/pdf...W-QP-JAN10.PDF

    And the markscheme is here
    http://store.aqa.org.uk/qual/gce/pdf...W-MS-JAN10.PDF

    How am I supposed to know how to draw this. Surely I can draw it however I want as long I put a node where they have told me :confused:

    Thanks
    There must be nodes at places where the string is in a fixed point in space - i.e. the bridges. The wavelength is assumed to be constant, so the nodes must be evenly spaced.
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    Ok thank you.
    Does the wave then have 5 nodes and 4 antinodes?
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    (Original post by user1-4)
    Ok thank you.
    Does the wave then have 5 nodes and 4 antinodes?
    Yes it does.

    Are you also going to be sitting this exam in the summer?

    I am finding diffraction, diffraction gratings, springs and moments the most difficult topics for me to understand.

    Are you able to give me any tips/practice exercises that helped you understand them?
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    yes I am sitting it in the summer. For diffraction and diffraction gratings all you really need to know is what the letter in the equation stand for. Once you know that when they ask you a worded question just put some easy numbers in and see what result you get.

    e.g. If wavelength increases what happens to fringe spacing.
    Put every number as 1 and work out fringe spacing. then increase wavelength to 2 and see what happens to fringe spacing.

    I also find springs and moments hard. Aswell as stationary waves
    Any tips?
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    Ahh okay I'll practice my diffraction grating skills

    My main help for stationary waves was: http://www.s-cool.co.uk/a-level/phys...standing-waves

    Moments seems so easy in terms of it's equation, but I never know where to take moments from
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    wow thanks.
    Oh and resolving forces in equilibrium and pulley stuff are hard
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    Yes forces in equilibrium is so difficult!

    I have a couple of threads on here that are forces in equilibrium questions that I cannot do :bawling:
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    I just saw. I'll also comment on your threads now
    They are REALLY hard. And gravitational potential energy and kinetic energy and things like that. :dontknow:
 
 
 
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