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    Im having a lot of problems in setting up and solving these equations....can any1 help????
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    (Original post by ladoooo)
    Im having a lot of problems in setting up and solving these equations....can any1 help????
    Theres a list of differential equations for P1, P2 and P3 at http://www.pixelfairies.co.uk/?conte...ifferentiation if that helps
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    I dont mean thsoe differential equations...i mean when they give u a passage and u hav 2 set up the differential eqaution...such as newtons law of cooling.
    There was a question like it in june 2003 paper....i couldnt do it

    Help anyone???
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    hum, i couldnt do a), although i looekd on ajimal and didnt have a clue. can someone explain this please?

    ive done the rest though!
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    (Original post by kikzen)
    hum, i couldnt do a), although i looekd on ajimal and didnt have a clue. can someone explain this please?
    ...
    Basically , two constants multiplied together are still a constant!

    Since the tank is emptying, then the rate (of increase) of fluid flow is negative.

    dV/dt = -K√ V, K positive

    V = πr²h
    dV/dh = πr²
    dh/dV = 1/πr²

    dh/dt = (dh/dV).(dV/dt)
    dh/dt = 1/(πr²).(-K√ V)
    dh/dt = 1/(πr²).(-K√ (πr²)√ h)
    dh/dt = -K√ h/√ (πr²)
    dh/dt = -k√ h, k a positive constant and k = K/√ (πr²)
 
 
 
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