add the potentials
V=k/r * (q1+q2+q3)
r= 11.5 cm
I get the right answer.
The triangle is an equilateral triangle: 20 cm x 20 cm x 20 cm.
What is the value of the electric potential at the center of the triangle if q1= 5.0 nicroC , q2= 5.0 microC, q3= -4.2 microC?
V = 4.52 x 10^5V
but I can not get this answer.
What is the value of the electric potential at a point midway between and i the figure ?
V = V
2 answers
20 cm /2 = 10 cm or .1 m
(.1/r)=cos30degree
Now r = (cos30Degree)*.1 = .115 m
Then use the electric potential formula
V = (k/r)*(q1+q2+q3)
V = ((9 * 10^9 N.m^2/C^2)/.115 m)*(5*10^-6 C + 5*10^-6 C - 4.2*10^-6 C)
V = 4.52 x 10^5 V
(.1/r)=cos30degree
Now r = (cos30Degree)*.1 = .115 m
Then use the electric potential formula
V = (k/r)*(q1+q2+q3)
V = ((9 * 10^9 N.m^2/C^2)/.115 m)*(5*10^-6 C + 5*10^-6 C - 4.2*10^-6 C)
V = 4.52 x 10^5 V
2 answers