What is the magnitude of the electric field

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Homework Help Overview

The problem involves calculating the magnitude of the electric field generated by a charged object, specifically a cat with a net charge of -54.1 µC, at a distance of 4.01 m. A follow-up question considers how the electric field would change if the distance were tripled.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the appropriate equations to use for calculating the electric field, with some confusion noted regarding the difference between force and electric field calculations. There are attempts to clarify the correct formula and to identify potential errors in calculations.

Discussion Status

The discussion includes attempts to clarify misunderstandings about the calculations involved. Some participants provide guidance on the correct equation to use, while others express uncertainty about specific numerical inputs. There is a mix of interpretations regarding the calculations, but productive dialogue is occurring.

Contextual Notes

Participants are working under the constraints of homework rules, which may limit the amount of direct assistance they can provide. There is also a noted confusion about constants used in the calculations, indicating a need for careful attention to detail in the problem setup.

shimizua
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Homework Statement


A cat rubs her back on the carpet, and acquires a net charge of -54.1 uC. What is the magnitude of the electric field at a distance 4.01 m from the cat?
and
What would the magnitude of the electric field in the previous problem be,
if the distance from the cat were now tripled?


Homework Equations


F=kq/r^2


The Attempt at a Solution


F=8.9E9(54.1E-6)/4.01^2
my answer came to 2.86E4 N/C which is wrong.

obviously i should be able to get the second part once i understand what i am doing wrong in the first part
 
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You have calculated the force due to the electric field, not the field itself.

I believe the eq you are looking for is:
<br /> E=\frac{Q}{4\pi\epsilon_0r^{2}}<br />
 
shimizua said:
F=8.9E9(54.1E-6)/4.01^2
my answer came to 2.86E4 N/C

it shouldn't :redface: … did you enter 8.5 instead of 8.9?

(and isn't it 8.988, or just 9.0, anyway?)
 
k so i did

E=54.1E-6/4*3.14*8.85E-12*4.01^2 and got 2.7E4 N/C which still was wrong. what else did i do wrong?
 
Never mind I got it. i was using the right equation, lol i guess i did just enter a number in wrong. funny cause i did it like 10 times. thanks though tiny-tim
 

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