If steve throws the football 50 mentees in 3 seconds what is the average speed (velocity) of the football

(50 meters) / (3 seconds) = (50/3) (meters/sec) = (16 and 2/3) meters/sec .

Speed is correct.

It's NOT velocity.

They're different things.

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