Two rectangular pieces of plane glass are laid one upon the other on a table. a thin strip of paper is placed between them at one edge so that a very thin wedge of air is formed. the plates are illuminated at normal incidence by 545 nm light from a mercury-vapor lamp. interference fringes are formed, with 19.0 fringes per centimeter. find the angle of the wedge.

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s

spare some change and give it to the poor

explanation:

plz : ((

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