Mass of Object in Uniform Electric Field

[gotpink74]

Homework Statement

An object with a net charge of 18 µC is placed in a uniform electric field of 597 N/C, directed vertically. What is the mass of the object if it floats in the electric field?

Homework Equations

F=kq1q2/r^2

The Attempt at a Solution

dont understand at all

 

[rock.freak667]

Ok, start with the first statement, they said the electric field is directed upwards. So what force is upwards?

Naturally what force will be exerted on the mass downwards?

Now put these two equal to each other.

 

[gotpink74]

thank you i solved it