Help with electron in electric field problem

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Homework Help Overview

The problem involves an electron moving in a uniform electric field, with specific parameters given for its initial velocity, charge, and mass. The goal is to find the acceleration of the electron in units of m/s².

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the use of the equations of force and acceleration, with one participant attempting to apply the formula a = Eq/m. There are questions about the correctness of the arithmetic and the need to specify the direction of acceleration.

Discussion Status

The discussion is ongoing, with participants checking calculations and considering the requirements of the electronic homework service. There is no explicit consensus, but some guidance has been offered regarding the potential need for directional notation in the answer.

Contextual Notes

Participants note that the electronic homework service is strict about answer formats, and there is uncertainty about whether a negative answer is acceptable. The need for clarity in vector direction is also under consideration.

Nano
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Homework Statement



An electron has an initial velocity of 5 ×
105 m/s in the x direction. It enters a uni-
form electric field ~E = (440 N/C) ˆj which is
in the y direction.
The charge and mass of an electron are
1.6×10−19 C and 9.11×10−31 kg, respectively.
Find the acceleration of the electron.
Answer in units of m/s2.

Homework Equations



F=eq
F=ma


The Attempt at a Solution



I tried using those two equations and coming up with a = Eq/m, but that's not the correct answer!
 
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Nano said:
I tried using those two equations and coming up with a = Eq/m, but that's not the correct answer!
That should work just fine. Show what you did.

Since acceleration is a vector, they may want you to specify its direction as well.
 
440 * (1.6e-19)/ (9.11e-31) = 7.2777e13 m/s^2

I'm submitting it into an electronic homework service, which is very picky. I tried submitting a negative answer too, but that's is not correct either...
 
Nano said:
440 * (1.6e-19)/ (9.11e-31) = 7.2777e13 m/s^2
Check your arithmetic. (I suspect it's just a typo here.)

I'm submitting it into an electronic homework service, which is very picky. I tried submitting a negative answer too, but that's is not correct either
Since the directions were given using unit vectors, perhaps that's what they want in the answer.
 
Doc Al said:
Check your arithmetic. (I suspect it's just a typo here.)

Aha! Thank you!
 

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