When is two waves are told in phase 2) phase difference 3) phase difference = pi/2,pi/4 4) formula to calculate phase difference 6) how phase difference occurs in ray optics also formula pls urgent

Aman throws a football straight into the air. as it rises, it slows down. which type of energy is the football gaining?

(a) calculate the number of electrons in a small, electrically neutral silver pin that has a mass of 10.0 g. silver has 47 electrons per atom, and its molar mass is 107.87 g/mol. (b) imagine adding electrons to the pin until the negative charge has the very large value 1.00 mc. how many electrons are added for every 109 electrons already present

Ihave a density of 1.61g/cm^3 and a mass of 28g. find the missing value