Charge q is applied to a circular disk of ebonite of radius a by rubbing it while it is rotating. in this way the surface charge density becomes proportional to the radial distance from the center. show that the electric field strength on the axis of the disk at an axial distance ℎ from the center is √ − √ .

Ishmael wants to go on vacation with his friend's family. what's the best way he can persuade his parents to say yes? a he can tell them that he will be sad and stay in bed if he can't go. b he can explain that the vacation will be educational and safe. c he can say that he'll hate his parents if they don't let him go. d he can ask them for the money that he needs for the trip.