Electrostatic Field concept question

[physics213]

Homework Statement

A ping pong ball covered with a conducting graphite coating has a mass .005 kg and a charge -4 microC. What electric field will exactly balance the weight of the ball?

Homework Equations

qE = mg

The Attempt at a Solution

I know how to get the magnitude of the electric field using the equation above. I just don't understand the conceptual part of this question: Which way is the electric field going (up or down)? Any help would be appreciated...thanks

 

[rock.freak667]

since weight acts downwards, I'd assume the electric field move the charge upwards.

 

[harvellt]

It would have to act parallel and in the opposite direction to the force of gravity.

 

[physics213]

well another similar problem had the electric field pointing downward with the particle having a negative charge.

 

[rock.freak667]

well another similar problem had the electric field pointing downward with the particle having a negative charge.

So which way will the electric field point to move the -4uC charge upwards?

 

[physics213]

So which way will the electric field point to move the -4uC charge upwards?

I would assume upwards but I'm not really sure. This seems like a really simple concept but i can't figure it out.

 

[rock.freak667]

I would assume upwards but I'm not really sure. This seems like a really simple concept but i can't figure it out.

Electric fields move from positive to negative. So if you place a negative charge in that field, it will move towards the positive side.