When a wire that has a large diameter and a length l is connected across the terminals of an automobile battery, the current is 40 a. if we cut the wire to half of its original length and connect one piece that has a length l/2 across the terminals of the same battery, the current will be:
a) 160a
b) 40a
c) 10a
d) 80a
e) 20a

the body's situation won't change the forces are equal opposit and on the same body

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