Which of these correctly describes whether a girl holding a ball in the same position is doing work on the ball? a. the girl is doing work on the ball because the energy of the ball changed, even though it is not displaced. b.the girl is doing work on the ball because the energy in her muscles changed, even though the ball is not displaced. c.the girl is doing no work on the ball because she is not exerting any net force on the ball. d.the girl is doing no work on the ball because the ball is not displaced.

Imagine an isolated positive point charge q (many times larger than the charge on a single proton). there is a charged particle a (whose charge is much smaller than charge q) at a distance from the point charge q. on which of the following quantities does the magnitude of the electric field created by charge q at particle a's position depend? check all that apply.the type of the charge on the charged particle athe relative orientation between q and a (while the distance between q and a is fixed)the specific location of the charged particle a (while the distance between q and a is fixed)the amount of the charge on the point charge qthe specific location of the point charge q (while the distance between q and a is fixed)the distance between the point charge q and the charged particle athe amount of the charge on the charged particle a