Point charge a is located at point a and point charge b is at point b. points a and b are separated by a distance r. to determine the electric potential at the mid-point along a line between points a and b, which of the following mathematical approaches is correct? a. the difference in the absolute value (the sign of the charges does not enter into the calculation) of the two electric potentials is determined at a distance r/2 from each of the charges. b. the algebraic sum of the two electric potentials is determined at a distance r/2 from each of the charges, making sure to include the signs of the charges. c. the electric potential due to each charge is determined at a distance r/2 from each of the charges and an average is taken of the two values. d. the vector sum of the two electric potentials determines the total electric potential at a distance r/2 from each of the charges

B. The algebraic sum of the two electric potentials is determined at a distance r/2 from each of the charges, making sure to include the signs of the charges.

Explanation:

Total electric potential is the sum of all the electric potential. And because electric potential is a scalar quantity you have to account for the signs.

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.