A child sits at the top of a slide at a playground. He wiggles forward slightly, and then slide all the way down with no further effort. Explain the source of the force acting on the child, and how you would calculate the work being done.

force of gravity

Explanation:

The force of gravity is following up on the child, making him  slide all the way down with no further effort.

the work being done on him is the distance he slides vertically times the force applied, which is the height of the slide ( meters), times his weight (newtons)

the answer is a. hope this .

electric field is a function of 1/r^2

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