-Dos corredores parten simultáneamentedel mismo punto de una pista circular de 200 m y corren en direccionesopuestas. Uno corre con una rapidez constante de 6.20 m/s, y el otro, conrapidez constante de 5.50 m/s. ¿Cuándo se encuentren primero? a) ¿Cuánto tiempohabrán estado corriendo?, y b) ¿qué distancia desde el punto de salida habrá cubiertocada uno?

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