1. The problem statement, all variables and given/known data 1. A balloon is charged with excess charge. This balloon is then put in a space with a uniform electric field pointing towards +x direction. When there is no wind around, this balloon is observed moving towards the -x direction. What is the sign of excess charge on the balloon? (A ) Positive. (B ) Negative. (C ) Not enough information. (D) Neutral. 2. Relevant equations None 3. The attempt at a solution I thought the answer was "A" but that is incorrect. I thought so only because of the second to last sentence. I thought of the whole "opposite charges attract." I also don't understand the significance of saying which direction the electric field is in, only that it points from positive to negative.