Recent content by equant

Homework Statement A certain metal sphere of volume 1cm^3 has a mass of 7.5g and contains 8.2 x 10^22 free electrons. How many electrons must be removed from each of two such spheres so that the electrostatic force of repulsion between them just balances the force of gravitational attraction...

ok, and in this case u = xy. I was thinking that they had to be dealt with separately, but now I see it. Thank you very much.

The typo was in my post. I corrected it. Sorry about that. With that now corrected, I'm still not sure how they get from the one step to the next.

Homework Statement I'm reading a chapter out of Elem. DE 6th Edition by Rainville and Bedient (Ch 4 pg 61) titled integrating factors found by inspection. To explain it, the authors start with an equation, which is grouped to become: y dx + x dy + x^3y^2 dy = 0 which then becomes...

"collinear parallel" vs "collinear" I'm trying to understand the difference between "collinear parallel" and "collinear" when describing vectors. "Collinear parallel" seems mean that the vectors are "on the same line" and that the angle between them is zero; so they are in the same direction...