Which of the following statements are true? Check all that apply. Check all that apply. When all charges are at rest, the surface of a conductor is always an equipotential surface. Electric field lines and equipotential surfaces are always mutually perpendicular. The potential energy of a test charge increases as it moves along an equipotential surface. An equipotential surface is a three-dimensional surface on which the electric potential is the same at every point. The potential energy of a test charge decreases as it moves along an equipotential surface.

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j

Answer sample (c); // would be best because the percentage of the energy in an incident wave that remains in a reflected wave from this material is the smallest;