Static Electricity and particles

AI Thread Summary
The discussion revolves around calculating the net force on three charged particles: +70 µC, +48 µC, and -80 µC, arranged in a line with specific distances. The user initially applies the formula F=kq1q2/d² but struggles with the correct application, particularly in considering the signs of the forces and their vector nature. They are advised to draw a diagram, analyze one charge at a time, and carefully account for the distances and directions of the forces. Despite performing calculations, the user receives feedback that their final answer is incorrect, indicating a misunderstanding in the superposition of forces. The thread emphasizes the importance of correctly applying vector addition and considering the effects of charge signs on force direction.
me_and_you
Messages
6
Reaction score
0

Homework Statement



Particles of charge +70, +48, and -80 \muC are placed in a line, in the previous order. The center one is .35 m from each of the others. Calculate the net force on each charge due to the other two.

Homework Equations



F=kq1q2/ d2


The Attempt at a Solution



I found the force between each but according to my teacher I am not doing this correctly could someone please tell me how i should go about doing this problem.
 
Physics news on Phys.org
Draw a diagram. Consider one charge at a time.

The ones on the end will be .35 and .7 distant from the other 2 respectively.

Be careful with the signs. Be careful with the units.

Be careful that you have taken care to note the direction of the force in each equation. (+,-) attracts and same sign repels.

Since forces are vectors then you must take that into account when you add them by superposition.
 
I thought that's what I was doing but after trying again i got the same wrong answer, I'm so confused about wht i should do with this problem!
 
Show your calculation then for the middle charge.
 
LowlyPion said:
Show your calculation then for the middle charge.

F1= (9x109)(70 x 10-6)(48x10-6)/ .352

this equals: 246.86

F3= (9x109)(-80 x 10-6)(48x10-6)/ .352


this equals: -282.1

Then i did
(246.862)+ (-282.12)= Q2

Q= 374C

but according to my teacher this is wrong... can you tell me what it is that I am doing wrong?
 
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Thread 'Struggling to make relation between elastic force and height'
Hello guys this is what I tried so far. I used the UTS to calculate the force it needs when the rope tears. My idea was to make a relationship/ function that would give me the force depending on height. Yeah i couldnt find a way to solve it. I also thought about how I could use hooks law (how it was given to me in my script) with the thought of instead of having two part of a rope id have one singular rope from the middle to the top where I could find the difference in height. But the...
Back
Top