Runner A is initially 8.0 mi west of a flagpole and is running with a constant velocity of 2.0 mi/h due east. Runner B is initially 6.0 mi east of the flagpole and is running with a constant velocity of 7.0 mi/h due west. How far are the runners from the flagpole when they meet?

because if the tool that you are using is not balanced it there would be false mass.

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.

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.