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Homework Help: Equilibrium and tension (2 questions)

  1. May 11, 2008 #1
    1)A mass 'm' is dropped from a spring with constant 'k'. find the time it takes to reach equilibrium.

    im pretty sure i can use this eqn
    T = 2*PI*sqrt(m/k)






    2)find the tension at the lowest point of the pendulum, with length L and mass M.

    there will be zero work done by tension at the bot, it is at a r. angle. im thinking you have to use k + U = k_0 + U_0 for conservation of mechanical energy, but i was also thinking of using the y component of the problem.

    T - m*g = a * m

    a = v^2 / r

    T = m*g + m*(v^2/r)

    v = omega*r and omega = sqrt (g/L)

    T = m*g +(m*g) / L


    this dosnt seem right
     
  2. jcsd
  3. May 11, 2008 #2
  4. May 12, 2008 #3

    Doc Al

    User Avatar

    Staff: Mentor

    You will certainly need that result.

    Looks good. How will you find the speed? From what height was it released?

    :confused:
     
  5. May 12, 2008 #4
    wouldnt v or h be given in the question? these are just general questions i have right now not h/w or anything.

    but
    for velocity

    (mv^2)/r = m*g

    v^2 = g*r


    im not to sure what to do for height
     
    Last edited: May 12, 2008
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