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    I've done it properly this time. Nice opportunity to practice using LaTeX writing.

    Finding velocity before string breaks:
    a and s are common so v will be the same for both at the point the string breaks.

    For A and B:
    Energy before= Energy after + any work done against friction

    3\times2mg= \frac{1}{2}mv^2 +\frac{2}{2}mv^2 + 2\times2mg + \frac{3}{5}mg + \frac{1}{4}\times\frac{4}{5}mg

    GPE is taken as 0J at the initial position of A and at ground level for B.

    v=\frac{2\sqrt 5g}{5}

    For the distance in b):
    Energy of A before= Energy of A after + any work done against friction

    \frac{1}{2}\times\frac{4m\times5  g}{25} +\frac{3}{5}mg= \frac{3}{5}mgl + \frac{1}{4}\times\frac{4}{5}mg(l-1)

    l is 1.5. Therefore total distance moved is 1.5 metres since l includes the 1 metre moved before the string breaks.
    • Study Helper

    Study Helper
    (Original post by Killjoy-)

    Re Latex. \sqrt{5g} with the 5g in braces.

    (Original post by ghostwalker)

    Re Latex. \sqrt{5g} with the 5g in braces.
    Thanks! Its annoyingly difficult to type without it.
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Updated: October 2, 2011

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