Electric Field and Kinematic Equations for Acceleration and Time Calculations

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SUMMARY

The discussion focuses on the application of electric field concepts and kinematic equations to calculate acceleration and time. The user employed the formulas F=qe, a=qe/ma, and x=vit + 1/2t^2 to derive results for two scenarios. However, the calculated values of acceleration and velocity were deemed unreasonable, with one result suggesting a time of 2.38 x 10^6 seconds and a velocity of -1.25 x 10^21 m/s, both of which exceed physical limits. The community emphasized the importance of showing detailed calculations to identify errors in the approach.

PREREQUISITES
  • Understanding of electric force and charge (F=qe)
  • Knowledge of mass and acceleration relationship (a=qe/ma)
  • Familiarity with kinematic equations (x=vit + 1/2t^2, vf=vi + at)
  • Basic principles of physics regarding speed limits (speed of light)
NEXT STEPS
  • Review the derivation of kinematic equations in physics
  • Study the relationship between electric fields and particle motion
  • Learn about the implications of relativistic speeds in physics
  • Practice problem-solving with detailed calculations in electric field scenarios
USEFUL FOR

Students studying physics, particularly those focusing on electric fields and kinematics, as well as educators seeking to clarify common misconceptions in these topics.

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: 769
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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