Please don\'t just guess. I will only rate well if you explain and show the work
ID: 2198479 • Letter: P
Question
Please don't just guess. I will only rate well if you explain and show the work A charge of +Q and a charge of +2Q are separated by a distance r. The electric force of +2Q on +Q has a magnitude of F and is directed to the right. Which one of the following statements is correct regarding the electric force of +Q on +2Q? (A) The electric force of +Q on +2Q has a magnitude F and is directed to the right. (B) The electric force of +Q on +2Q has a magnitude F and is directed to the left. (C) The electric force of +Q on +2Q has a magnitude 2F and is directed to the right. (D) The electric force of +Q on +2Q has a magnitude 2F and is directed to the left. (E) The electric force of +Q on +2Q is zero.Explanation / Answer
The answer is B - The electric force of +Q on +2Q has a magnitude F and is directed to the left.
The reason for this is as follows...
The formula for force between charges is F = kqq/r2. Force is a vector quantity, so direction is important. Since the formula for force takes account of both charges in the same formula, if the force on one is F, then the force on the other must also be F. This is just Newton's Third Law in another form. That is, for every action, there is an equal an opposite reaction. Thus the magnitude of the force on one must be the same as on the other. In this case they are both defined as F given in the question.
You can also use Newtons Third Law to prove the "opposite" part. Since the first charge produces a force to the right, the other must produce a force to the left. You can also see that since the charges are both positive they repel each other. The one charges pushes the other to the right, so that charge has to push the other to the left.
Equal and opposite forces - Magnitude equal and direction opposite.