Ajutati-ma va rog.. am nevoie urgent de rezolvare .două bile identice, avînd sarcinile electrice egale cu +8 nc şi +2 nc, interacţionează cu o forţă egală cu 1,6 mn. bilele au fost puse în contact, apoi îndepărtate pînă la distanţa iniţială. care este valoarea forţei de interacţiune în acest caz?

a and b sometimes have a positive value

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