What is the Charge of a Ball in an Electric Field?

[KhaNgo]

An electric field causes the 5.0 g point charge to hang at a 20 angle. What is the charge of the ball

I don't have the figure but it looks like a simple pendulum hanging at the angle of 20 degree

Homework Statement

E= 100,000 N/C
m of the ball = 5g
Angle =20 degree

e0= 8.85*10^12

Homework Equations

E = F (electrostatic) on p / p (charge)

F = (K q1 q2)/r12^2

q=E*r^2*4pi*e0

The Attempt at a Solution

I have no clue

 

[LowlyPion]

An electric field causes the 5.0 g point charge to hang at a 20 angle. What is the charge of the ball

I don't have the figure but it looks like a simple pendulum hanging at the angle of 20 degree

Homework Statement

E= 100,000 N/C
m of the ball = 5g
Angle =20 degree

e0= 8.85*10^12

Homework Equations

E = F (electrostatic) on p / p (charge)
F = (K q1 q2)/r12^2
q=E*r^2*4pi*e0

The Attempt at a Solution

I have no clue

Draw a force diagram.

Figure what needs to be in balance for the pendulum and weight to be at that angle.

 

[KhaNgo]

So basically, there will be tension, gravity and electric field act on it
and gravity and electric field will have x,y component but how can we figure out Tension?
So saying the ball doesn't move we can set everything =0 but we don't have tension

 

[KhaNgo]

Never mind, I've found the right answer...We actually don't need Tension to solve it
Thanks for great hint