Electric potential & isosceles triangle

AI Thread Summary
The discussion focuses on calculating the electric potential at the midpoint of the base of an isosceles triangle formed by three charges. A positive charge of 5.7 x 10^-9 C is at the top vertex, while two negative charges of 5.4 x 10^-9 C are at the bottom vertices. The user initially applied the principle of superposition but miscalculated by not accounting for the different signs of the charges. After receiving feedback, the user acknowledged the oversight regarding the charge signs. The conversation emphasizes the importance of considering charge polarity in electric potential calculations.
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Three charges are located at the vertices of an isosceles triangle. A positive charge, of 5.7 x 10^-9 C is located at the top, and two negative charges each of 5.4 x 10^-9 C are located at the bottom. The lengths of the 2 sides are 7.1 cm and the length of the base is 1.3 cm. Calculate the electric potential at the midpoint of the base. Answer in units of V.
I used the principle of superposition. I found that the length from the charge to the midpoint was .0065 m and the length of the other side when the triangle was cut in half was .0707 m.
So V= 9 x 10^9 [ (5.7 x 10^-9/.0707) + (5.4 x 10^-9 /.0065) + (5.4 x 10^-9/.0065)
So V= 1.57 x 10^4, but this isn't right... can someone please tell me what I'm doing wrong? Thanks in advance.
 
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I didn't check your arithmetic, but did you forget that the charges have different signs?
 
Yes I did.. thanks a lot!
 
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