A particle that has mass and charge is travelling from left to right through a uniform gravitational field and a uniform electric field. The gravitational field acts downwards. On this particle, the gravitational force and the electric force act in opposite directions. What could the sign of the charge on the particle be, and what is the direction of the electric field?
- Anegative, down
- Bnegative, up
- Cpositive, left
- Dpositive, right