Calculating Resistance of a Disk | Homework Problem Solution

  • Thread starter Thread starter Gyroscope
  • Start date Start date
  • Tags Tags
    Disk Resistance
Gyroscope

Homework Statement


A disk with width b and radius a.
An element of resistance is:

dR=\rho \frac{2\pi r}{bdr}

How do I integrate this?

Thanks in advance. :approve:

Homework Equations





The Attempt at a Solution

 
Physics news on Phys.org
I don't understand your volume element. You are trying to get the total resistance between what two places? A point on one edge of the disk to a point on the other side, or from the center out to the perimiter, or what?
 
It's the sum of the resistances of each ring of the disk.
 

Thread 'Direction of the magnetic field of an oscillating charge'

Hello everyone, I’m considering a point charge q that oscillates harmonically about the origin along the z-axis, e.g. $$z_{q}(t)= A\sin(wt)$$ In a strongly simplified / quasi-instantaneous approximation I ignore retardation and take the electric field at the position ##r=(x,y,z)## simply to be the “Coulomb field at the charge’s instantaneous position”: $$E(r,t)=\frac{q}{4\pi\varepsilon_{0}}\frac{r-r_{q}(t)}{||r-r_{q}(t)||^{3}}$$ with $$r_{q}(t)=(0,0,z_{q}(t))$$ (I’m aware this isn’t...
View full post »

Thread 'Initial conditions for orbits around a wormhole'

Hi, I had an exam and I completely messed up a problem. Especially one part which was necessary for the rest of the problem. Basically, I have a wormhole metric: $$(ds)^2 = -(dt)^2 + (dr)^2 + (r^2 + b^2)( (d\theta)^2 + sin^2 \theta (d\phi)^2 )$$ Where ##b=1## with an orbit only in the equatorial plane. We also know from the question that the orbit must satisfy this relationship: $$\varepsilon = \frac{1}{2} (\frac{dr}{d\tau})^2 + V_{eff}(r)$$ Ultimately, I was tasked to find the initial...
View full post »

Similar threads

Electric Field due to a disk of radius R in the xy-plane
Replies
7
Views
2K
Kinetic energy of a disk that is rolling and not slipping
Replies
4
Views
2K
Magnetic field of a rotating disk with a non-uniform volume charge
Replies
1
Views
2K
Rotating and tilting charged disk induces a voltage inside a ring
Replies
11
Views
2K
How Does a Rotating Disk Generate Torque in a Magnetic Field?
Replies
1
Views
2K
Heat flux through a material with variable heat conductance
Replies
2
Views
2K
A falling resistive disk in uniform magnetic field
Replies
17
Views
1K
Finite dual disk capacitor: estimating charge distribution
Replies
1
Views
1K
Vector torque problem: Force applied to a disc
Replies
6
Views
4K
Electric field due to a charged disk
Replies
12
Views
2K

Hot Threads

Recent Insights

Back
Top