# Finding the tension in the thread

## Homework Statement

A tiny, 0.60g ball carries a charge of magnitude 8.0 mircoC. It is suspended by a vertical thread in a downard 300 N/C electric field. What is the tension in the thread if the charge on the ball is (a) positive, (b) negative?

## Homework Equations

E=F/q or E=mg/q

When i use that formula something is missing because ive tried to match the final answer from the other thread with the same exact problem he wants to solve too

Last edited:

Try finding the electric force on the ball caused by the field.

• JKhim
Still finding the final formula for this problem

(a) 8.3 mN; (b) 3.5 mN.

All the forces are vertical. In both cases you have an electric force and gravitational force, in one case they are opposite.
In what directions does a positive vs. negative charge move in the electric field? Does a positive charge go against or
along the field lines?

haruspex
Homework Helper
Gold Member
2020 Award
When i use that formula something is missing
it will save a lot of time and guesswork if you post your own working and answer in the first place.

Orodruin
Staff Emeritus