
#1
Feb511, 07:33 PM

P: 118

1. The problem statement, all variables and given/known data
Suppose I had a large sphere with 10 protons and 10 neutrons. Another sphere with 2 protons and 2 electrons. How many different electrostatic forces would be acting between the two spheres? What would be the likely net force between the two spheres in this example? How would this change if I stripped 2 electrons away from the larger sphere? 2. Relevant equations Coulomb's law F=k(q1^2)(q2^2)/d^2 3. The attempt at a solution what do they mean by how many "different electrostatic forces"? Would the net force be 0? and i don't think it would change even if i stripped away 2 electrons? 



#2
Feb511, 08:08 PM

Emeritus
Sci Advisor
PF Gold
P: 5,198

What is q1 (the charge on the first sphere)? What is q2 (the charge on the second sphere). Plugging these into coulomb's law will give you the total (net) force between the spheres.
Each sphere has a number of electric charges on it, and each charge on the first sphere interacts with every charge on the second sphere. Of course, the sum of these interactions should just be the same as the total one you calculated using the above method (by just looking at overall charge totals). 



#3
Feb611, 10:06 AM

P: 118

wait... is the charge 10 and 2 respectively?
also, what do they mean by how many different electrostatic forces? 



#4
Feb611, 11:14 AM

Emeritus
Sci Advisor
PF Gold
P: 5,198

Force between two charged bodies! 



#5
Feb611, 01:34 PM

P: 118

if you add them up.. it's 0.
....the electrostatic charge is just neutral because of the protons and electrons... 



#6
Feb611, 03:45 PM

Emeritus
Sci Advisor
PF Gold
P: 5,198

Yes. The net charge of two protons and two electrons is zero. So q2 is zero. So sphere 2 is uncharged and feels no force from sphere 1.




#7
Feb611, 07:55 PM

P: 118

so there are no electrostatic forces.
but the net force would be more positive if you did strip 2 electrons away from the larger sphere. is there a specific number for the "net force". would it be.. 6? 



#8
Feb611, 10:12 PM

Emeritus
Sci Advisor
PF Gold
P: 5,198

I don't understand the rest of your question. What does, 'is there a specific number for the 'net force'" mean? 



#9
Feb711, 07:32 AM

P: 118

i was wondering if the net force would change though.
because it wouldn't be 0, would it? or it would stay 0 because the smaller sphere is 0? 


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