Which statement best defines work. A) Work is the time it takes to move an object once acted upon by a force
B) Work occurs when balanced forces act on a object and cause movement in the direction of these forces
C) Work occurs when a force causes motion of an object, and this motion is the same directional the applied force
D) Work is the distance over time that an object moves once acted on by a force

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