Electric potential & isosceles triangle

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SUMMARY

The discussion centers 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 at the top and two negative charges of 5.4 x 10^-9 C at the bottom vertices. The user initially applied the principle of superposition but incorrectly summed the contributions from the charges without accounting for their signs. The correct formula for electric potential, considering the signs of the charges, is crucial for accurate results.

PREREQUISITES
  • Understanding of electric potential and Coulomb's law
  • Familiarity with the principle of superposition in electrostatics
  • Basic geometry of isosceles triangles
  • Knowledge of unit conversions (e.g., cm to m)
NEXT STEPS
  • Review the principle of superposition in electrostatics
  • Study the calculation of electric potential from point charges
  • Learn about the effects of charge signs on electric potential
  • Explore geometric properties of isosceles triangles in physics problems
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Students and professionals in physics, particularly those studying electrostatics, as well as educators looking for examples of electric potential calculations involving multiple charges.

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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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