Three equal charges, Q coulombs are located at the vertices of a triangle as shown in the figure. The charges are connected together by strings as shown in the figure. If the length of each string is L, determine the tension in the strings.
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Since all the charges are of equal sign, each Q is experiencing a repulsive force from the other two. Since the string holds them all in equilibrium all these forces add up to zero.
I.e., F13 + F12 + T1 + T3 = 0
We can write F13 = Q1 E3 and F12 = Q1 E2 Where E3 and E2 are given by coulomb's law. F13 is the force acting on charge Q1 ...
Solution as a MS word attachment. Easy to understand and clear.