Two ions are placed on the x-axis. One has a charge of +e and is located at the origin. The other has a charge of -4e and is located at x = +d, where d 0. Where on the x-axis could a third charge be placed such that the net electrostatic force on it caused by the other two charges is zero?

Question

Two ions are placed on the x-axis. One has a charge of +e and is located at the origin. The other has a charge of -4e and is located at x = +d, where d > 0. Where on the x-axis could a third charge be placed such that the net electrostatic force on it caused by the other two charges is zero?

anonymous · Answer

Remember that a charge cannot affect itself. Now, at what r is F=kqQ/r^2 equal for both q's?

sanaelshazly · Answer

shall I substitute 0 instead of F

anonymous · Answer

Remember that the vector sum of the forces must be 0. We have kq (the product of the constant and the central charge in question). We know Q for both possible charges. We know r∈[0,+d], or in terms of the charge in question, r for the left charge, and d-r for the right charge. By solving for the said denominator, you can write r in terms of d, which should give you your answer.

anonymous · Answer

Is there a part you're having difficulty with?

anonymous · Answer

If I wasn't clear, please tell me.

sanaelshazly · Answer

No No !! it was clear enough =) 
Thank You !! =)

anonymous · Answer

hello

anonymous · Answer

i can your lesson. i m from Turkey. i m a çivil engineer