28 If it takes 1,697 m to stop a car initially moving at 46 m/s, what distance is required to stop a car moving at a quarter
of the initial speed under the same conditions?

no. dot product   =0 when vecs at right angles

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