Impossible heisburg uncertainty question that makes no sense

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Homework Help Overview

The discussion revolves around a quantum mechanics problem involving the Heisenberg uncertainty principle, specifically concerning the uncertainty in the speed and position of a hypothetical quantum duck named Fuzzy. The problem provides specific parameters, including mass and initial position constraints.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss various attempts to apply the uncertainty principle, with one participant expressing confusion over their calculations and another questioning the method used to derive a specific numerical result. There is also a discussion about the interpretation of speed versus velocity in the context of the problem.

Discussion Status

The conversation is ongoing, with participants sharing their calculations and questioning each other's reasoning. There is no clear consensus, but some guidance is being offered regarding the interpretation of the uncertainty in speed and the application of the relevant equations.

Contextual Notes

Participants mention the constraints of online homework systems and the potential differences in textbook interpretations regarding the treatment of speed and velocity in uncertainty calculations.

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Homework Statement



Suppose Fuzzy, a quantum-mechanical duck, lives in a world in which h = 2πJ · s. Fuzzy has a mass of 1.80 kg and is initially known to be within a pond 1.00 m wide. (a) What is the minimum uncertainty in the duck's speed?
1(b) Assuming this uncertainty in speed to prevail for 5.40 s, determine the uncertainty in Fuzzy's position after this time.

Homework Equations


xp=h/4(3.14)


The Attempt at a Solution


tried it a million different ways
 
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Well can you tell us what you tried, and tell us the right answer that you are failing to get?
 
im doing online homework
 
(a) I plugged all the numbers into the equation using 2pie for h and I get 8.88 and its off by orders of magnitude (b) I have no idea
 
How did you get 8.88?
if delta x * m * delta v = h/4 = 2pi / 4 = pi / 2
then
delta v = Pi / (2 * 1 m * 1.8 kg) = Pi Js / 3.6kgm
pi/3.6 is NOT 8.88 ... it's going to be a little less than 1

and that's not even considering the fact that the uncertainty in speed should be half of the uncertainty of velocity (though I've even seen some textbooks that don't even consider the fact that velocity can be in both directions, and take the uncertainty in velocity to be the uncertainty in speed...however, the book that i learned quantum mechanics from had the uncertainty in speed as half the uncertainty in velocity for all the questions ...i don't know how your online service works, but if 8.88 is off by EXACTLY an order of magnitude, then the real answer would be 0.87 and not half of that)
 
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