# 2.7 Conductors and electric fields in static equilibrium  (Page 5/11)

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(a) Using the symmetry of the arrangement, show that the electric field at the center of the square in [link] is zero if the charges on the four corners are exactly equal. (b) Show that this is also true for any combination of charges in which ${q}_{a}={q}_{d}$ and ${q}_{b}={q}_{c}$

(a) What is the direction of the total Coulomb force on $q$ in [link] if $q$ is negative, ${q}_{a}={q}_{c}$ and both are negative, and ${q}_{b}={q}_{c}$ and both are positive? (b) What is the direction of the electric field at the center of the square in this situation?

Considering [link] , suppose that ${q}_{a}={q}_{d}$ and ${q}_{b}={q}_{c}$ . First show that $q$ is in static equilibrium. (You may neglect the gravitational force.) Then discuss whether the equilibrium is stable or unstable, noting that this may depend on the signs of the charges and the direction of displacement of $q$ from the center of the square.

If ${q}_{a}=0$ in [link] , under what conditions will there be no net Coulomb force on $q$ ?

In regions of low humidity, one develops a special “grip” when opening car doors, or touching metal door knobs. This involves placing as much of the hand on the device as possible, not just the ends of one’s fingers. Discuss the induced charge and explain why this is done.

Tollbooth stations on roadways and bridges usually have a piece of wire stuck in the pavement before them that will touch a car as it approaches. Why is this done?

Suppose a woman carries an excess charge. To maintain her charged status can she be standing on ground wearing just any pair of shoes? How would you discharge her? What are the consequences if she simply walks away?

## Problems&Exercises

Sketch the electric field lines in the vicinity of the conductor in [link] given the field was originally uniform and parallel to the object’s long axis. Is the resulting field small near the long side of the object?

Sketch the electric field lines in the vicinity of the conductor in [link] given the field was originally uniform and parallel to the object’s long axis. Is the resulting field small near the long side of the object?

Sketch the electric field between the two conducting plates shown in [link] , given the top plate is positive and an equal amount of negative charge is on the bottom plate. Be certain to indicate the distribution of charge on the plates.

Sketch the electric field lines in the vicinity of the charged insulator in [link] noting its nonuniform charge distribution.

What is the force on the charge located at $x=8.00 cm$ in [link] (a) given that $q=1\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{μC}$ ?

(a) Find the total electric field at $x=1.00 cm$ in [link] (b) given that $q=5.00 nC$ . (b) Find the total electric field at $x=11.00 cm$ in [link] (b). (c) If the charges are allowed to move and eventually be brought to rest by friction, what will the final charge configuration be? (That is, will there be a single charge, double charge, etc., and what will its value(s) be?)

(a) ${E}_{x=\text{1.00 cm}}=-\infty$

(b) $2\text{.}\text{12}×{\text{10}}^{5}\phantom{\rule{0.25em}{0ex}}\text{N/C}$

(c) one charge of $+q$

(a) Find the electric field at $x=5.00 cm$ in [link] (a), given that $q=1.00\phantom{\rule{0.25em}{0ex}}\text{μC}$ . (b) At what position between 3.00 and 8.00 cm is the total electric field the same as that for $–2q$ alone? (c) Can the electric field be zero anywhere between 0.00 and 8.00 cm? (d) At very large positive or negative values of x , the electric field approaches zero in both (a) and (b). In which does it most rapidly approach zero and why? (e) At what position to the right of 11.0 cm is the total electric field zero, other than at infinity? (Hint: A graphing calculator can yield considerable insight in this problem.)

(a) Find the total Coulomb force on a charge of 2.00 nC located at $x=4.00 cm$ in [link] (b), given that $q=1.00\phantom{\rule{0.25em}{0ex}}\text{μC}$ . (b) Find the x -position at which the electric field is zero in [link] (b).

(a) 0.252 N to the left

(b) $x=6.07 cm$

Using the symmetry of the arrangement, determine the direction of the force on $q$ in the figure below, given that ${q}_{a}={q}_{b}\text{=+}7\text{.}\text{50}\phantom{\rule{0.25em}{0ex}}\text{μC}$ and ${q}_{c}={q}_{d}=-7\text{.}\text{50}\phantom{\rule{0.25em}{0ex}}\text{μC}$ . (b) Calculate the magnitude of the force on the charge $q$ , given that the square is 10.0 cm on a side and $q=2\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{μC}$ .

(a) Using the symmetry of the arrangement, determine the direction of the electric field at the center of the square in [link] , given that ${q}_{a}={q}_{b}=-1\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{μC}$ and ${q}_{c}={q}_{d}\text{=+}1\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{μC}$ . (b) Calculate the magnitude of the electric field at the location of $q$ , given that the square is 5.00 cm on a side.

(a)The electric field at the center of the square will be straight up, since ${q}_{a}$ and ${q}_{b}$ are positive and ${q}_{c}$ and ${q}_{d}$ are negative and all have the same magnitude.

(b) $2\text{.}\text{04}×{\text{10}}^{7}\phantom{\rule{0.25em}{0ex}}\text{N/C}\phantom{\rule{0.25em}{0ex}}\left(\text{upward}\right)$

Find the electric field at the location of ${q}_{a}$ in [link] given that ${q}_{b}={q}_{c}={q}_{d}\text{=+}2\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{nC}$ , $q=-1\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{nC}$ , and the square is 20.0 cm on a side.

Find the total Coulomb force on the charge $q$ in [link] , given that $q=1\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{μC}$ , ${q}_{a}=2\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{μC}$ , ${q}_{b}=-3\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{μC}$ , ${q}_{c}=-4\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{μC}$ , and ${q}_{d}\text{=+}1\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{μC}$ . The square is 50.0 cm on a side.

$0\text{.}\text{102}\phantom{\rule{0.25em}{0ex}}\text{N},$ in the $-y$    direction

(a) Find the electric field at the location of ${q}_{a}$ in [link] , given that ${q}_{\text{b}}=+10.00\phantom{\rule{0.25em}{0ex}}\mu \text{C}$ and ${q}_{\text{c}}=–5.00\phantom{\rule{0.25em}{0ex}}\mu \text{C}$ . (b) What is the force on ${q}_{a}$ , given that ${q}_{\text{a}}=+1.50\phantom{\rule{0.25em}{0ex}}\text{nC}$ ?

(a) Find the electric field at the center of the triangular configuration of charges in [link] , given that ${q}_{a}\text{=+}2\text{.}\text{50}\phantom{\rule{0.25em}{0ex}}\text{nC}$ , ${q}_{b}=-8\text{.}\text{00}\phantom{\rule{0.25em}{0ex}}\text{nC}$ , and ${q}_{c}\text{=+}1\text{.}\text{50}\phantom{\rule{0.25em}{0ex}}\text{nC}$ . (b) Is there any combination of charges, other than ${q}_{a}={q}_{b}={q}_{c}$ , that will produce a zero strength electric field at the center of the triangular configuration?

(a) $\stackrel{\to }{E}=4.36×{\text{10}}^{3}\phantom{\rule{0.25em}{0ex}}\text{N/C},\phantom{\rule{0.25em}{0ex}}35.0º$ , below the horizontal.

(b) No

which comes first emotion or thinking
Emotions
Keerthi
true
james
either could come first. arguing for the supremacy of one over the other may not hold, ceteris paribus.
Oyetoro
Depends on which part of brain is dominated in individual.
Gaurav
thinking. it's a thought that provokes an emotion
Free
I often saw cat in my dreams nd thats why i m afraid of cats.. wherever i see cat i just escape from that place what is this nd why this happens
usually whatever you see during the day or what impacted you in the slightest, will appear in your dream.
The
What kind of dream? Why you afraid of cat because you dream about it? Bad dream?
Yoselin
i saw cat nd lizard nd oftenly they attack me nd i could not save my self nd then i wakeup nd feels fear
Tasneem
from childhood i like cata nd play with it but now because of that dreams i dont like cats nd lizards
Tasneem
some times you feels uncomfortable to cat have around you ,but still you should take out from fear..
Kanzul
yes i want to take out this fear but i cannot face cat wherever i see cat i feel fear
Tasneem
you know your weakness, that is it..you should see the videos on cats ..it will be enough for you.. after that you see the variation in your mind illusions
Kanzul
if it is more fear, you take Consultancy from psychiatrist..
Kanzul
thats the problem i can't see cats videos i dont wanna see cats or lizards
Tasneem
what you think? that cat attack on you..😅
Kanzul
is there any past memory relate with this?
Kanzul
yes i think that cat will attack me but i just saw cats in dreams attacking me
Tasneem
can you understand hindi?
Kanzul
urdu
Tasneem
اچھا ہے..آپ نے کبھی علم نفسیات اور خواب کی تعبیرات کی کتابیں پڑی ہے..اپنے آپ کو درست کرنے کے لیے یہ سب سے بہترین نسخہ ہے..
Kanzul
the cat is your mind reflecting your Self. you are not afraid of cats, the cat is just a symbol for the fear you have of life and death. Cat is life, cat eats lizard, cat brings death. You are either the cat or the lizard, in your subconscious mind.
Will
Will
it may have bitten in your childhood stage,and you still remember it
hamed
Where is semantic memory u mentioned the name but didn't disscuss the topic..?
If u have want to make happy ur babby not by blood but by heart by giving all ur time to them but ur mother wants u to gave that time on urself and ur studies and that makes her happy and mom doesnot know that i accept her as my babby she thought she is just my friend
Iqra
Actually she is 4 years younger than me but i love her and said my baabby to her what should i do now?
Iqra
If anyone can help me plz do it i am super depressed
Iqra
Hlo Iqra...
IAS
Hi!
Iqra
?
Iqra
If u r in real conjunction wd him say ur mom fluently that I wana make him mine I feel depressed
IAS
Mom has best hearing power as to understood her/his baby
IAS
But my mom dont accept that she think i am just runing my life
Iqra
U have to b very clear wd ur mom
IAS
Where from u
IAS
Well i didn't tell about that but i said i love her she is like my soul sister and i love to gave her time but she said if u want to meat her itsok but dont talk on phone because u consume alot time on her and thats not fair
Iqra
Bhai i am from earth
Iqra
How can I suggest u it WL take alot time
IAS
Actually she dont like her because i gave 3 to 4 hours on phone to her
Iqra
Where frm u r?
IAS
Okay thank u so much bhai i think i got my answer
Iqra
whats your relation with her ? where you meet her nd why your mom forbid you from talking with her
Tasneem
Ur most welcome sister
IAS
She live in my neighborhood we are frnds from childhood but she is 4 yeras younger than me thats why i called her my bachaa and i gave alot of time to her because she have no sister brother and also no frnd and my mom dont like that
Iqra
Because 3 to 4 hours on phone she dont like usage of phone so much no one did accept me infront her thats why she is against her she dont hate her she just said meet her face to face not on phone
Iqra
Okay thank u so much all of u now i am feeling good and got my answe also
Iqra
yeah your mom said right but dont talk too face to face sometimes things that are above limits leads to problems
Tasneem
welcome😊
Tasneem
Yeah u are right inshallah everything will be alright soon
Iqra
Thank u
Iqra
inshaa allah..
Tasneem
i have a question?
Melissa
Yea
Iqra
Iqra
what is one strategy that would promote positive risk taking behavior?
Melissa
I dont know
Iqra
Why do I get upset when my girlfriend doesn't tell me she loves me back in front of her friends?
Do not depend on her, or don't hope just take care of her ..it doesn't matter that how much she love you..matter that how much you love her..
Kanzul
Because you're insecure, read "The Rational Male" by Rollo Tomassi if you want to make sure that you and your girlfriend are/remain satisfied in your relationship
Leon
and don't listen to Kanzul, don't be a pushover
Leon
may be you are suspicios if she stay around her male friends
Kanzul
Thank you both, yeah umm it makes sense that I'm insecure and yeah I mean I do love her alot the thing is it's not with her Male friends it's in general.
Apollo
But also what is considered a pushover so I can avoid that Leon
Apollo
what is this that a persom constantly saw dream from very early age till now nd saw same dream what is this
Candy
how
Tasneem
Candy
dayshavoo
Candy
thank you
Tasneem
😊
Tasneem
samething keeps happening,repeat
Candy
why do I have dreams of my boyfriend boss
Because you love him and his memories. Or that you are reminded of him very often.
Jobin
There are some explanation why we have dream. It can be just your brain picking random memory in your brain when you sleep (eventhough we sleep our brain still working) and this random memory your brain pick out become your dream
Kelly
👍
Jobin
or this boss left an impression in you, but it doesn't necessarily mean you have a romantic feelings towards this person. Maybe this boss just do some random thing and it left an impression in your memory and you still think about it subconsciously when you sleep and it manifested itself in ur dream
Kelly
That is perfectly normal and no cause for worry. You might not want to tell your boyfriend though ;)
Leon
What do you think is the reason for your friends or the family members coming into the dreams especially wet dreams? And after that what's the feeling of the person?
Jobin
how to get rid of fearful avoidant issues
Do you think that seminary student needs psychological studies?
I think it's best for high schoolers.. we all should be aware of what we are
Alexsus
Yes definitely, especially in an age like this were more and more I've observed students not knowing what they truly are and not knowing how to deal with psychological issues. Plus, it gives them the advantage of knowing how to deal with other people with different ideas and issues.
Tav
Absolutely. How would you be able to make any serious decisions in your life, when you are a mess and don't understand your feelings, motivation and reasoning behind this or that issue. Moreover, I think whether you are a seminary student or not, you should also be taught critical thinking skills.
Sofia
Thank you all
Jobin
whats is schizophrenia
long-term mental disorder of a type involving a breakdown in the relation between thought, emotion, and behavior, leading to faulty perception, inappropriate actions and feelings, withdrawal from reality and personal relationships into fantasy and delusion, and a sense of mental fragmentation.
Amber
What is burn out syndrome?
Jobin
Emotional and physical exhaustion which appears after a long period of stress.
Avram
what is social conflict
a conversation with someone & having conflict with .
Candy
Soory Guys hope you ar doing well Im in strong desire to get this kind of book INTRODUCTORY PSYCHOLOGY but ther cost is too and I'm not able to buy it If you see this announcement please I need soft copy even few please
jacobo
Anybody who is able to access this book just help even soft copy to saves me Im so soory
jacobo
Deen social conflict means misunderstand occurred among the people in a certain social context can be caused by poor governance
jacobo
what is top-notch?
excellent? the best?
Travis
the very best.
Snuffles
best of something. above the expectation
Jem
something like expert level
Evil
zenith
Syed
Hi! what is introspection?
jacobo
the ultimate best.. of excellent quality
Melissa
honor and respect
Randall
Understanding
Candy
Hi! This book INTRODUCTORY PSYCHOLOGY I'm not able to buy anybody can help me even soft copy
jacobo
i want some pdf books who can help me
Leon
is there any website where I can get a true diagnosis of a personality disorder I think I may possess? I can't seek therapy due to insurance complications
Well most websites that offer actual medical diagnoses cost money or they will connect you to a doctor for some sort of meeting.
Elise
yeah I've been looking for a decent site for around a year now and that's all Ive found thank you
Bailey
Yeah it is quite hard to find a reliable site.
Elise
diagnosis couldn't get from a websites. you have to refer a doctors for a consultation.
patience
hi
Surya
Kanzul
Compare and contrast situational influences and dispositional influences and give an example of each. Explain how situational influences and dispositional influences might explain inappropriate behavior.
what is an ethical consideration that is what a search for my research is seeking out the truth what lies in the darkness and it's hidden by the light
Rev
Ethical consideration includes the risk of doing your research
Mary
***cirt.gcu.edu/research/developmentresources/tutorials/ethics
Amanda
as well as the research can not have lasting affects on the subjects.
Amanda
Is this live
Little
We as researchers should not harm the subjects of our research, be it the population under study or the selected sample. I think ethical consideration requires that we disclose as much as is practically possible about the requirements of the research to all concerned.
Abel
It is ethically sound also to to acknowledge others' findings wherever we reference them in our research because we are to build and grow the body of knowledge by building on the research others have done. This is my contribution.
Abel
What is CBT?
cognitive behavioral therapy
Joni
When they use this CBT?
zahir
what is cbt
Timothy
mostly used to help treat anxiety and depression related diagnosis. But it's used in other types of mental health issues.
Joni
cognitive behavioral therapy. As stated earlier in this discussion.
Joni
Thank yoi
zahir
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