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Homework Help: 1D Thermo problem, something is wrong

  1. Dec 12, 2004 #1
    A startled armadillo leaps upwards so that it rises to .56 m in a time .21 s.

    Note: I use a web-submitting thing for my answers. So it tells me what is right and wrong.

    A: What was the armadillo's initial speed when it left the ground?
    3.70 m/s - this part is correct.

    B: What is its current speed at the height .56 m?
    1.64 m/s - this part is also correct.

    C: How much higher will the armadillo rise before it reaches the peak of its jump?

    This is causing some huge problem. No idea why either, my answer seems to be right to everyone I show it to.

    V^2 Final = V^2 Init + 2 ad

    V^2 Final = 0 (it'd be that instant it stops before beginning to fall back down)

    0 = ( 3.70 m/s ^ 2 ) + 2 (-9.8 m/s) d

    This will give the full distance.

    = 13.69 - 19.6d

    19.6d = 13.69
    d = .695 m
    d = .70m (significant digits)

    how much will it rise above the .56?

    .70m - .56m = .14m - Says I am wrong.
    .70m - says I am wrong.
    .13 (maybe I rounded bad) - still says I am wrong.

    My work looks perfect, can someone please tell me what I did wrong?
  2. jcsd
  3. Dec 13, 2004 #2


    User Avatar
    Science Advisor

    To two digit accuracy, 0.14 m certainly is correct.
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