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Homework Help: Need help with this

  1. Oct 9, 2004 #1
    A weight of mass 2.00 kg hangs on a lineair spring with spring constant k= 3.25N/m^2. The weight is held at height y=0 so that the spring is not extended and exerts no force on the weight. When the weight falls, there is a damping force is proportional to the velocity. The initial velocity of the weight is zero. At time t=0, the weight is released. It falls and executes damped oscillations. Eventually, it comes to rest. For this situation, Newtons second law can be written as : m*(d^2*y/d*t^2)=-(dy/dt)-(k*y)-m*g
    Here -(dy/dt) is the damping force, -ky is the force exerted by the spring and -mg is the force of gravity

    Question: let y_final be the height of the weight after it stops moving..what is y_final?

    I dont know how to solve this....pls who can give me hints?
  2. jcsd
  3. Oct 9, 2004 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Sounds like a trick question. Hint: When the mass comes to rest, it will be in equilibrium.
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