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Homework Help: Jumping Bean Physics

  1. Aug 27, 2006 #1
    A jumping bean jumps vertically upward from the edge of a table. It has a speed of 10 m/s when it reaches half of its maximum height.
    a. How high does it rise?
    b. What is its velocity and acceleration 1 second after it jumps?
    c. 3 seconds after?
    d. What is its average velocity during the first half second?

    Okay so I'm a big noob. I think the acceleration is 9.8 m/sec^2 due to gravity. I think I can add 9.8 m for every second it rises but I'm not sure. Any help at all with this problem is greatly appreciated.
  2. jcsd
  3. Aug 27, 2006 #2


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    Not quite. The bean jumps vertically, but gravity is acting downward, so once the bean is launched with some initial velocity, it starts slowing down.

    Let H = maximum height, at which point the vertical velocity is zero.

    at h = H/2, v = 10 m/s, and the acceleration, g = 9.8 m/s2.

    How about writing some equations that relate height h(t), time t and vertical velocity v(t)?
  4. Aug 27, 2006 #3
    Do you know the kinematic equations?

    As in [tex]\Delta x = v_0 t + \frac{at^2}{2}[/tex]?

    If you don't, then I can see why you're having trouble with this problem.
  5. Aug 27, 2006 #4
    No I don't. I've only been taught 5 very basic physics formulas such as
    a= Vf - Vi/t
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