Electric Field and Kinematic Equations for Acceleration and Time Calculations

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Homework Help Overview

The discussion revolves around the application of electric field concepts and kinematic equations to calculate acceleration and time. Participants are analyzing the correctness of their approaches to solving the problem using formulas related to force and motion.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants describe their attempts to calculate acceleration using the formula a = qe/ma and to find time using kinematic equations. Questions arise regarding the validity of their results and the reasoning behind their calculations.

Discussion Status

Some participants have provided their calculated results, which have prompted others to question their reasonableness. There is a call for more detailed explanations of the calculations to identify potential errors. Multiple interpretations of the problem setup are being explored.

Contextual Notes

Participants express concern over the magnitude of their results, suggesting that they may be unreasonable based on physical constraints, such as the speed of light. There is also a note about the necessity of showing work to facilitate understanding and correction.

khuliso

Homework Statement



upload_2017-10-26_1-6-59.png

Homework Equations


F=qe, a= qe/ma, x= vit + 1/2t^2

The Attempt at a Solution


(a) i used the formula a= qe/ma to calculate the acceleration and then substituted in this kinematic equation x= vit + 1/2t^2 then i solved for t taking the initial velocity as zero.
(b) i used the same thinking but using the kinematic equation vf= vi + at

so i wanted to know if i have done the problem correctly , if i am wrong please give me a clue on how to approach this kind of problems
 

Attachments

  • upload_2017-10-26_1-6-59.png
    upload_2017-10-26_1-6-59.png
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Physics news on Phys.org

Homework Statement


upload_2017-10-26_1-21-15.png

-e = -1.9x10^-19 c , me= 9.1x10^-31 kg

Homework Equations


F=qe, a= qe/ma, x= vit + 1/2t^2

The Attempt at a Solution


(a) i used the formula a= qe/ma to calculate the acceleration and then substituted in this kinematic equation x= vit + 1/2t^2 then i solved for t taking the initial velocity as zero.
(b) i used the same thinking but using the kinematic equation vf= vi + at

so i wanted to know if i have done the problem correctly , if i am wrong please give me a clue on how to approach this kind of problems
 

Attachments

  • upload_2017-10-26_1-21-15.png
    upload_2017-10-26_1-21-15.png
    12.7 KB · Views: 781
We cannot tell you if you have done the problem correctly if you don't tell us what answer you got.
 
number (a) my answer is 2.38 x 10^6 s
(b) my answer is -1.25 x 10^21 m/s
 
khuliso said:
number (a) my answer is 2.38 x 10^6 s
(b) my answer is -1.25 x 10^21 m/s
(a) This is about 280 days. Without doing the calculation, I think this is unreasonable.
(b) The speed is 11 orders of magnitude higher than the speed of light. I think this is also unreasonable.

Please show the details of your calculation and how you got these numbers. Then someone should be able to point out where you went wrong. It's also possible that when you write it out for posting, you will pinpoint where you went wrong by yourself. It happens sometimes.
 
How are we going to know if you did it correctly if you do not show us exactly what you did and tell us what results you got?

khuliso said:
x= vit + 1/2t^2
This is incorrect. I would suspect a typo, but you have written it in the same way twice. Make sure you get the relation correctly.
 

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