Electric Field Homework: Acceleration = 1e18 m/s^2

[apalmer3]

Homework Statement

http://img206.imageshack.us/img206/7900/physicsml8.jpg


Note: Acceleration=1e18 m/s^2

The Attempt at a Solution

I've tried to do the ones marked with a red x, but I'm really not sure how... any hints would be greatly appreciated!

 

[physixguru]

First tell us why u answered it as zero electric field?