When you find the electric flux emerging/inducing through curved surface, a. The area vector as to be perpendicular to the surface somewhere . b. The surface cannot be curved very much; then you can treat is as though it were flat. c. You must divide the surface into pieces that are tiny enough to be almost flat. d. The surface must be spherical. e. Actually the flux through a curve surface cannot be calculated.

b

explanation:

bc its just b

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