Calculating Potential at Point Above Uniformly Charged Square of Side 2a

  • Thread starter Thread starter Phymath
  • Start date Start date
  • Tags Tags
    Charge Surface
AI Thread Summary
The discussion focuses on calculating the electric potential at a point above the midpoint of a uniformly charged square with side length 2a and surface density ρ. The potential is expressed using a double integral involving the distance from the charge elements to the point of interest. Participants express frustration over the complexity of evaluating the integral, particularly noting that it often leads to logarithmic expressions. There is also a query about the differences in integrating for a small rod versus the square, highlighting the need for clarity in limits. Ultimately, the conversation reflects the challenges of solving this physics problem without a provided solution.
Phymath
Messages
183
Reaction score
0
a square of side 2a is uniformly charged with a surface density \rho
find the potential at a point distance a directly above the midpoint of one of the sides, express your answer as a numerical multiple of k_e \rho a.

wow ok soo... i got this going for me
<br /> k \rho \int^a_{-a} \int^a_{-a} \frac{1}{\sqrt{(x-x&#039;)^2 + (y-y&#039;)^2 + z^2}}dy&#039; dx&#039; where (x,y,z) is the point simple enough..how do i evaulate this...i know it goes all natural log on me...but damn what do i do then!? suggestions anyone?
 
Physics news on Phys.org
Find the potential at the point due to a small rod of length 2a and then integrate from a to a+2a
 
how will that be different? other then a change of limits?
 
Is the solution
2 ln[4+(2)^1/2]* (KP2a)^2 ?
 
probley not considering it asks for a numerical multiple of kpa...
no solution is given i just have to figure it out

make it easier..sorta what's this?

<br /> k \rho \int^a_{-a} \int^a_{-a} \frac{1}{\sqrt{(-x&#039;)^2 + (-a-y&#039;)^2 + a^2}}dy&#039; dx&#039;
 
Last edited:
how come everytime i do one of these no one answers lol...
 
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}...
Back
Top