# Search results for query: *

1. ### Describing Rolling Constraint for Rolling Disk With No Slipping

I believe we are keeping ##\phi## constant, since ##R## is constrained to move along the angle ##\phi##. I think I know what you're getting at; I'm not calculating the differential correctly. I can't in general vary ##x## without varying ##y## since ##R## is constrained to move along ##\phi##...
2. ### Describing Rolling Constraint for Rolling Disk With No Slipping

Thanks for the reply - looks like I completely messed this one up! If I start from the start and now say that ##R## is the distance from the origin to the center of the disk, I see what you're saying about ##\frac{dy}{dx}=tan\phi##. Then, expanding ##dR##, I get (remembering to put in the...
3. ### Describing Rolling Constraint for Rolling Disk With No Slipping

Let ##R=\sqrt{x^{2} + y^{2}}##. Then \begin{align}v_{tangential}&=\frac{dR}{dt} \nonumber\\ &=\frac{dR}{dx}\frac{dy}{dt} + \frac{dR}{dy}\frac{dy}{dt} \nonumber\\ &=\frac{x}{R}\frac{dx}{dt} + \frac{y}{R}\frac{dy}{dt} \nonumber\\ &= cos\phi \frac{dx}{dt} + sin\phi \frac{dy}{dt}.\nonumber...
4. ### Electric Dipole Moment, Potential, and Field of contiuous charge

I see my mistake! Thanks for the correction guys :)
5. ### Electric Dipole Moment, Potential, and Field of contiuous charge

I'm resurrecting a zombie thread here, but I think the answer given for the dipole potential is incorrect. TSny provides the correct method for obtaining it, despite saying that OP's answer for the dipole potential is correct. To expand a little, if we find ##V_{dipole}(x, y, z)## we get...