**1. Homework Statement**

http://loncapa.vcu.edu/res/vcu/phys202/zzImages/two-charges-forces.bmp

Problem#1:

Two identical conducting balls, A and B, of identical masses m = 10 kg, are suspended in equilibrium by insulating massless strings in length L = 3 m. Both balls make the same angle θ = 30° with the vertical axis. Both masses have equal charge. You can ignore the size of the balls.

**What is the magnitude of the Coulomb force, i.e. electric force, exerted on A from B due to the charges? (From free body diagram analysis)**

What is the amount of charges (do not worry it is positive charge or negative charge) on each ball?

What is the amount of charges (do not worry it is positive charge or negative charge) on each ball?

Problem#2:

Two identical conducting balls, A and B, of identical masses m = 40 kg, are suspended in equilibrium by insulating massless strings in length L = 2 m. Both balls make the same angle θ with the vertical axis. The angles are very small such that small angle approximation applies (i.e. tan θ = sin θ). Both masses have equal charge Q= 3e-06 C. You can ignore the size of the balls.

**What is the distance r between the two balls?**

**2. Homework Equations**

F=q1*q2*k/(r^2)

where k=9*10^9

E=F/Q

**3. The Attempt at a Solution**

the only part i figured out (sadly) is the 1st part to find the Coulomb force. and that was only because the teacher gave us the equation :(

((40kg*10)/cos(30))*sin(30)=i got 57.7N for coulomb force

still don't no why thats the answer, but at least i no how to get it.

but i don't know what to do from here. i don't know how to find r so i assume it is L given (=3m). so i don't know how to find q (amt of charges).

for problem#2 i am stumped. i don't understand angle approximation and i can't use the cos/sin method that our teacher gave us. so wat do i do??