Hurry ! the best i will give the brainliest

The speed of both cars is the same ... 80 km per hour.

But their velocities are different, because DIRECTION is part of velocity, and their directions are different.

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