Questions about the ionosphere... is gravity lying under it? how does that operate the whole gravity limited by the perimeter of I think it's the ionosphere? correct?

(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

Stephanie lives in california, and her cousin thomas lives in france. which coordinate system would be most useful if the two wanted to observe the same meteor shower and discuss their observations over online chat as they're making them? a. horizontal b. equatorial c. azimuth-altitude d. celestial or azimuth-altitude

Arock, thrown straight up, takes 4.2 seconds to reach its max height (g=9.8m/s) what was the initial velocity? what was its maximum height?