If an electron is accelerated from rest through a potential difference of 1200V find its approximate velocity at the end of this process. (qe = 1.6 x 10^-19 C; me = 9.1 x 10^-11kg)

2.1 × 10^7 m/s

Explanation:

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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