What am I doing wrong? Potential Difference

AI Thread Summary
The discussion revolves around a homework problem related to potential difference and energy conservation. The user attempted to solve part B by using the energy conservation equation but found that their approach did not yield the expected results. They proposed dividing the initial speed by two to find the potential difference but expressed confusion over the outcome. Additionally, they considered an alternative method of calculating the fraction of energy decrease needed to reduce speed to half. The conversation highlights the challenges in applying energy conservation principles to determine potential difference in the context of the problem.
kamehamehaaa
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Homework Statement


On attachment. Part B only. I got C.


Homework Equations


mass of proton is 1.673*10^-27
q0 = 1.60*10^-19


The Attempt at a Solution



For part B I thought I could divide the intial speed by 2 and plug it back into the energy conservation equation:

.5mv^2 + q0V1 = .5mv^2 + q0V2 and solve for (V1 - V2) which would be the potential difference but it doesn't seem to work.
 

Attachments

  • 20.20 part b c.JPG
    20.20 part b c.JPG
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That should work just fine. (Show what you actually did.)

Another way to look at it is: By what fraction must the total energy be decreased to bring the speed to half its initial value? Compare that with the answer you got for part A.
 

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