When objects are charged by
they do not need to touch each other.

we need to know the time interval during which the force acts. impulse of force = momentum change

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

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr

snell's law

refractve index = sin incidence / sin refraction