Two light rays from a common point are refracted by a lens. A real image is formed when these two refracted rays A
diverge and appear to come from a single point.

B
converge to a single point.

C
travel in parallel paths.

D
totally reflect inside the lens.

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

answeralert drivers who drift off the road;