Recent content by Ali 2

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    Horizontal spring with friction

    ok i see what you mean ap123 the energy stored initially = the work done by the friction force 0.5*k*x0^2= C * mg * distance
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    Horizontal spring with friction

    hello ok the work done by the spring is 0.5*k*x02 - 0.5*k*x12 we know that x0=-0.1m but what is x1, since the 0.25m given in the question is the distance not the displacement??!?
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    Horizontal spring with friction

    Homework Statement A spring with negligible mass has a constant of 105 N/m. It has been compressed horizantally with a 2 kg mass for a distance of 0.1m. If the mass has moved after release for a distance of 0.25m, what is the coefficient of kinetic friction between mass and horizontal surface...
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    Can a Dynamical System Have Multiple Locally Stable Equilibria?

    hi yes, my question means: can the number of equilibria in the statement exceed one? The example you provided don't satisfy the requirement. The equilibrium 0 is unstable thanks.
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    Can a Dynamical System Have Multiple Locally Stable Equilibria?

    Hi all Suppose for a dynamical system \dot x=f(x) , x \in \mathbb R^n there exists finite number of isolated equilibria, each of which is locally stable (i.e eigenvalues of the associated Jacobian have negative real parts). My question is: Can this happen for more than one equilibrium...
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    Who took the GRE Subject Math Test ?

    Who took the GRE Subject Math Test ?? I am going to take the GRE Math next Saturday, I would like to ask you .. Did the practice test posted in the ETS site resemble well the real test you have took ? Is it more difficult or less .. ? Did the Princeton review ( Cracking the GRE Math)...
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    Rate of change of the magnitude of the displacement

    And that is what I thought about .. Thanks :smile: ,
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    Rate of change of the magnitude of the displacement

    If the displacement was given by \overrightarrow x (t) ( i.e vector valued function ) . Then the velocity is \overrightarrow v = \frac {d \overrightarrow x}{dt} The speed is the magnitude of v . But .. What is the derivative of the magintude of the displacement \frac {d...
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    What is the Exact Solution to 0.739085?

    The solution of the equation cos (x) = x can be given as applying the cosine function infinite nubmer of times to a starting point .. x = cos cos cos ... cos (a) In other words , the solution can be expressed as : x = \lim _ { n \to \infty } \cos ^ { \circ n } ( a )...
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    Dirac's Delta as a derivative of the unit step

    The Dirac detla or unit impulse function is defined as : \delta (t) = \left \{ \begin {matrix} \infty \quad \ t = 0 \\ 0 \quad : \ t \neq 0 \end{matrix} and the unit step function : u(t) = \left \{ \begin {matrix} 1 \quad \ t \geqslant 0 \\ 0 \quad : \ t < 0 \end{matrix} It is...
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    Solving ODE: How to Integrate Left Integral?

    It is not necessary to have an explicit relation, implicit relation is sufficuint
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    Solving ODE: How to Integrate Left Integral?

    Hi, I = \int \frac { dH} { a + b- c \sqrt H } Let u2= H >>> 2u du = dH \therefore I = \int \frac {2u } { a + b- c u } du = \frac {-2} {c} \int \frac { -cu + a + b- (a + b) } { a + b- cu } du = = \frac {-2} {c} \left( 1 - \frac { a + b} { -c } \int \frac { -c } { a + b- cu } du...
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    What Is the Identity for |sinx - siny| and |cosx - cosy| in Trigonometry?

    Hi, This is an inequality .. | \sin x - \sin y | \leq | x - y |
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    Find the result of this integration

    Waiting .. :zzz: !
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    Find the result of this integration

    Hi, Find the result of this integration:: \int_0^\infty \frac { e^ {-3x} - e^ {-4x} }{x} dx The members who know the answer previously please don't answer in order to make the other members think :cool: ! Best wishes ,
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