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Homework Help: Determining Uncertainty in Position using Heinsburg's Uncertainty Principle

  1. Apr 26, 2009 #1
    1. The problem statement, all variables and given/known data

    A 52.9 g ball moves at 12.2 m/s.
    If its speed is measured to an accuracy of
    0.04%, what is the minimum uncertainty in
    its position? Answer in units of m.

    2. Relevant equations

    delta x times delta p = 1/2 (h/2pi)

    3. The attempt at a solution

    I used the uncertainty of the speed to determine the minimum and maximum momentums for the ball. I used these to determine what delta p is equal to (0.6195648) and then substituted that number into the equation to solve for delta x. I used kilograms for the mass, which I believe are the correct units as opposed to just grams. If you could help me determine what I am doing wrong, that would be great! Thanks!
    1. The problem statement, all variables and given/known data
  2. jcsd
  3. Apr 26, 2009 #2


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    Homework Helper

    Welcome to PF.

    Δp*Δx ≥ ℏ/2

    Planck's constant is pretty small, so I'd think you should get a very small number here.

    h = 6.6*10−34

    And at that you are using ℏ which is h/2π.

    Your Δp = .0004*.6344 already, so Δx must be quite small as far as the minimum allowed uncertainty in Δx
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