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what do i need to know about SHM and circular motion watch

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    hi guys, im not to sure what i nned to know for SHM or how to answer some questions relating to it. I know the stuff about T being independent of amplitude and how to interprete the graphs, pendulum er... yea

    what else do i need to know? :confused:

    Also how do you go about answering a circular motion theory question, maybe about a cd spinning or a car trying to describing a circular path on an icy road. :confused:

    Thanx a lot
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    Have you tried checking your syllabus? Which one are you doing?
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    im doing Edexcel Phy 4.

    I have its just that when i did the exam in Jan after all my revision and preparation i got a low grade.:bawling: This is the only unit im stuggling on, i think dunno about phy 6. :afraid:
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    a) learn all the formulas
    b) learn all the explannations of weightlessness, centripetal force, free fall e.t.c

    All are explainned in this forum, you can use the search bit up the top. There is loads written about circular motion.
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    (Original post by nas7232)
    a) learn all the formulas
    b) learn all the explannations of weightlessness, centripetal force, free fall e.t.c

    All are explainned in this forum, you can use the search bit up the top. There is loads written about circular motion.
    Thanx mate
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    hmmm I tried to think it simple,I awlways exagorate the case so I dont know how to answer ,thanx to f1_fanatic and one of my friends who is still struggling with me totally getting the idea.I kinda understood it so there is a resultant force on a body this force acts perpendicular to the direction of motion causing the velocity to change it's direction,the change in velocity means there is an acceleration according to newtons second law F=ma so the direction of acceleration is the same as the direction of force which is towards the centre ,also as you know the mangitude of the velocity is constant while the direction changes
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    (Original post by habosh)
    hmmm I tried to think it simple,I awlways exagorate the case so I dont know how to answer ,thanx to f1_fanatic and one of my friends who is still struggling with me totally getting the idea.I kinda understood it so there is a resultant force on a body this force acts perpendicular to the direction of motion causing the velocity to change it's direction,the change in velocity means there is an acceleration according to newtons second law F=ma so the direction of acceleration is the same as the direction of force which is towards the centre ,also as you know the mangitude of the velocity is constant while the direction changes
    thanx,

    can we use newtons 1st law here to. cos i was thinking, according to newtons 1st law a body will continue at rest or continue(with constant speed in a straight line) unless acted upon by an unbalanced force.

    surely u can use it for centripetal acceleration of force because a constant unbalanced force is causing the car or object to move along a circular path and is directd towards the center because if it wasnt there it will go off at a tangent to the circle. F=mv^2/r where v is the linear speed and the change in direction is causing a change in direction hence its accelerating because its a vector quantity.

    Am i right?, i think i startd waffling
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    (Original post by andyj72)
    thanx,

    can we use newtons 1st law here to. cos i was thinking, according to newtons 1st law a body will continue at rest or continue(with constant speed in a straight line) unless acted upon by an unbalanced force.

    surely u can use it for centripetal acceleration of force because a constant unbalanced force is causing the car or object to move along a circular path and is directd towards the center because if it wasnt there it will go off at a tangent to the circle. F=mv^2/r where v is the linear speed and the change in direction is causing a change in direction hence its accelerating because its a vector quantity.

    Am i right?, i think i startd waffling
    ok your right...but the resultant force means what..it means there are an unbalance forces on a body
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    yes you are both right
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    (Original post by habosh)
    ok your right...but the resultant force means what..it means there are an unbalance forces on a body
    ok, so the unbalanced force on the body is causing it to follow a circular path because the force is directed towards the center.

    yes or no?

    its because with questions like this, actually physics question u hve 2 put down a lot of detail to get the marks and sometime i dnt know if im putting too little or even explianing it at all
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    (Original post by mik1w)
    yes you are both right
    so it means that u can use both newtons 1st and 2nd to describe circular motion?
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    (Original post by andyj72)
    so it means that u can use both newtons 1st and 2nd to describe circular motion?
    Well when you used F=mv²/r, you used Newton II too:
    F=ma, where a=v²/r
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    (Original post by andyj72)
    ok, so the unbalanced force on the body is causing it to follow a circular path because the force is directed towards the center.

    yes or no?

    its because with questions like this, actually physics question u hve 2 put down a lot of detail to get the marks and sometime i dnt know if im putting too little or even explianing it at all
    I know but I guess both are the same,I'm no centripetal force geniusbut I think that depends on the question they ask and putting newtons first law or saying that there is a resultant force is the same
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    (Original post by habosh)
    I know but I guess both are the same,I'm no centripetal force geniusbut I think that depends on the question they ask and putting newtons first law or saying that there is a resultant force is the same
    lol, i thought u might be

    yea it does depend on the question, i think we just hve 2 see when one comes up.
 
 
 
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