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asdf12312

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## 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?Problem#2:

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

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?**

## Homework Equations

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

where k=9*10^9

E=F/Q

## 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 that's 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??