Calculate the smallest possible distance between the two electrons

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Homework Help Overview

The discussion revolves around calculating the smallest possible distance between two electrons that are fired directly at each other with a specified speed. The subject area includes concepts from electrostatics and kinetic energy.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the relationship between kinetic energy and electrostatic potential energy, with one participant attempting to equate them. There is a suggestion that the initial kinetic energy should account for both electrons, leading to questions about the calculations involved.

Discussion Status

There is ongoing exploration of the problem, with participants questioning the correctness of the initial calculations and the provided answer in the textbook. Some participants express uncertainty about the assumptions made, while others suggest alternative interpretations of the problem.

Contextual Notes

Participants note discrepancies between their calculations and the textbook answer, leading to discussions about the potential for errors in the book or in their own reasoning. There is a mention of the need to consider the contributions of both electrons in the kinetic energy calculation.

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Question:
Two electrons are fired at 3.5 x 10^6 m/s directly at each other.
(a) Calculate the smallest possible distance between the two electrons.

Attempt:
I tried Ee=Ek for this question and this is how it went.
Note*(q1=q2)

Ee=Ek
kq^2 = 0.5mv^2
r
r= kq^2
0.5mv^2
= (9.0x10^9(N x m^2)/C^2)(1.6x10^-19C)^2
0.5(9.1x10^-31kg)(3.5x10^6m/s)^2
= 4.1x10^-11m


I don't seem to be getting the right answer. Can someone please tell me what I'm doing wrong?
 
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Your initial kinetic energy is not just 0.5mv^2, it's double that, since both electrons are moving. Try that.
 
The answer still doesn't match, but I'm thinking the book is wrong. So thank you=)
 
what is the answer?
 
It says 4.5x10^-6m.
 
i did it quickly, and i got the same answer u got in the first part. I did it another completely different way. interesting.. well i gtg.. i will try to look at this problem later.. but i don't think its right to assume the book is wrong.
 
They've taken the square root. I don't know why.
 
That would work if the electrostatic force was used, but I can't see how that fits.
 

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