Small clarification: applying Coulomb's Law

  • Thread starter Thread starter UselessLadder
  • Start date Start date
  • Tags Tags
    Coulomb's law Law
AI Thread Summary
The discussion clarifies the meaning of subscripts in Coulomb's Law equations, specifically in the context of forces between electric charges. The subscripts (13 and 23) indicate the specific interactions between charge pairs: force F1 is from charge 1 to charge 3, and force F2 is from charge 2 to charge 3. Despite initial confusion, it is confirmed that these subscripts are simply identifiers for the forces involved. The formula itself remains unchanged, focusing on the relationship between the charges and the distances. This clarification helps in understanding the application of Coulomb's Law in the given example.
UselessLadder
Messages
8
Reaction score
0

Homework Statement


Hi,

I'm studying electric charges and fields, and I have a quick question about this example in my book:
Untitled-1_zps8eb88ce6.jpg



Everything is straightforward except the subscripts (13 and 23) on r in the denominators of initial Coulomb equations for F1 and F2. In the next step they just plugged in the distances, so those numbers don't seem to do anything, and there are no subscripts in the original formula. So what are they?


Homework Equations



F = k [(q1q2)/r2]
 
Physics news on Phys.org
They just indicate that the force one is from charge 1 to charge 3. And the force 2 is from charge 2 to charge 3.
 
  • Like
Likes 1 person
Duh, I knew it had to be something obvious. Thank you!
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Conceptual understanding/question of guass and Coulomb’s law
Replies
5
Views
2K
Dependence of Coulomb's law on the medium
Replies
8
Views
3K
Force of Repulsion Between Charged Bodies: Calculating with Coulomb's Law
Replies
4
Views
2K
Calculating Charge and Force Using Coulomb's Law and Trigonometry
Replies
6
Views
8K
Gauss's Law vs Coulomb's law problem
Replies
3
Views
2K
Work, energy, power unit (coulombs)
Replies
2
Views
1K
Question regarding Coulomb's Law
Replies
8
Views
1K
Coulomb's law vs Electric Field
Replies
12
Views
5K
Three particles, finding Q of one of them (Coulomb's Law)
Replies
3
Views
2K
Coulomb's Law in 3D: Find Electric Force & Field
Replies
2
Views
3K

Hot Threads

Recent Insights

Back
Top