Two protons (each with q = 1.60x10^-19) in a nucleus are located 1x10^-15 m apart. How much electric force do they exert on each other?
[?] N

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue

the moving of the box is a result of centripetal force. think of that  as a car or a truck in this case creates a turn, the force of friction performing upon the turned wheels of the car runs centripetal force obligatory for circular motion for the things inside it.