Consider a conical surface (open) of height h and radius of the base r uniformly charged with surface charge density \sigma . choose the axes so that the vertex of the cone is at the origin and its axis of symmetry coincides with the axis oz . calculate the work of the electrostatic force exerted by the cone on a point charge q when that charge is taken from the vertex of the cone to infinity

uranium fissions/breaks up giving out energy and neutrons

current flows in a wire

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me