Question

three equal charges each having a charge 2×10^-6C are placed at the three corners of a right angle triangle of sides 3 cm 4 cm and 5 cm find the force on the charge at the right angled corner

Answer 1

Three equal charges each having a charge 2×10^-6C are placed at the three corners of a right angle triangle of sides 3 cm 4 cm and 5 cm find the force on the charge at the right angled corner 

Let us consider the charges to be A, B and C. Each charge is of 2 micro C. We need to find the resultant force at corner B.For this, we proceed in three steps:
1. Force between charges at B and A is F(AB) = 9 * 10^9  * [(2 * 10^-6)^2 ] / (3*10^-2)^2=40 N outwards

2. Force between B and C isF(BC) =   9 * 10^9  * [(2 * 10^-6)^2 ] / (4*10^-2)^2= 22.5 N outwards

3. Resultant Force is F(res) = sqrt(F1^2 + F2^2 + 2F1F2cos(90)) as the angle between the forces is 90 degrees

Therefore, the resultant force is 45.9 N