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    Can someone help me with this problem and thanks.

    A light inextensible string of length 4a has a particle A of mass attached at one end and a particle B of mass m attached at the other end. The string passes through a small smooth ring which is fixed at a point 0 at a distance 3a above a horizontal table. The system is hanging in equilibrium with 0B=2a when a smooth bead of mass 2m which is threaded on the string between 0 and B is released from rest at 0. The bead falls under gravity until it collides and adheres to the particle B to for a composite particle C.

    a) Given that the string remains taut, show that the speed of C immediately after the collision is squareroot(ga).
    b)find the speed of C immediately before it reaches the table.
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    (Original post by jakegreen)
    Can someone help me with this problem and thanks.

    A light inextensible string of length 4a has a particle A of mass attached at one end and a particle B of mass m attached at the other end. The string passes through a small smooth ring which is fixed at a point 0 at a distance 3a above a horizontal table. The system is hanging in equilibrium with 0B=2a when a smooth bead of mass 2m which is threaded on the string between 0 and B is released from rest at 0. The bead falls under gravity until it collides and adheres to the particle B to for a composite particle C.

    a) Given that the string remains taut, show that the speed of C immediately after the collision is squareroot(ga).
    b)find the speed of C immediately before it reaches the table.
    Is this from a past paper, coz i sorta remember doin it. I mite have the answer if it is.
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    Does this come with a diagram? Cos it would sure help...
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    there was no diagram and it is M2 Heinemann book,
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    (Original post by jakegreen)
    Can someone help me with this problem and thanks.

    A light inextensible string of length 4a has a particle A of mass attached at one end and a particle B of mass m attached at the other end. The string passes through a small smooth ring which is fixed at a point 0 at a distance 3a above a horizontal table. The system is hanging in equilibrium with 0B=2a when a smooth bead of mass 2m which is threaded on the string between 0 and B is released from rest at 0. The bead falls under gravity until it collides and adheres to the particle B to for a composite particle C.

    a) Given that the string remains taut, show that the speed of C immediately after the collision is squareroot(ga).
    b)find the speed of C immediately before it reaches the table.
    What is the mass of particle A?


    Edit: doh just read it again never mind
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    a) I can't seem to prove that v = sqrt(ga)... I always get v = sqrt(8/3 ga)

    b) Is the answer sqrt(7ga)?
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    http://homepages.nildram.co.uk/~walker12/Image2.jpg

    Part a worked ok dunno about part b it was a bit rushed. Will translate my scrawl into something readable later but gtg c ya.
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    is the mass of A m?
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    (Original post by BossLady)
    is the mass of A m?
    Yeah! It took me moment to figure it out too. But they are in equilibrium. ergo mass B = mass A = m.
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    After impacting, there's mg acting down on A and 3mg acting down on B/C
    So tension in string is now T, say.
    They are both subject to the same acceleration = a, say.

    Then,

    T-mg = ma
    3mg - T = 3ma

    3mg - mg = 4ma
    2mg = 4ma
    a = g/2
    =====

    v² = u² + 2as
    v² = ga + 2(g/2)(3a - 2a)
    v ² = ga + ga
    v² = 2ga
    v = sqrt(2ga)
    =========
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    (Original post by davedave)
    http://homepages.nildram.co.uk/~walker12/Image2.jpg

    Part a worked ok dunno about part b it was a bit rushed. Will translate my scrawl into something readable later but gtg c ya.
    Ah.. I see where I went wrong. I thought the distance from B to the table was 3a, not from O to the table.
 
 
 
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