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## Homework Statement

Two tiny spheres of mass = 6.60mg carry charges of equal magnitude, 72.0nC , but opposite sign. They are tied to the same ceiling hook by light strings of length 0.530m . When a horizontal uniform electric field that is directed to the left is turned on, the spheres hang at rest with the angle theta between the strings equal to 50° in the following figure.

What is the magnitude E of the field?

## Homework Equations

## The Attempt at a Solution

I know that q is moving towards the left towards the electric field.

I know that the tension in the x direction is Tx=Hcos∅

and in the y direction is Ty=hsin∅

I know the sum of the forces in the x direction ƩFx= hcos∅ + q

While the sum of the forces in the y direction is ƩFy=hsin∅-mg

Here is where I'm confused I have no idea how to find q. Would q just be 72?

In which case I get the magnitude of √ ƩFx^2 + ƩFy^2 = F0

then simply divde Fo/q to get E ?

i'm pretty confused some guidance would be awesome.

Thanks