A table tennis ball of mass 10g carries a charge of 0.04 micro Coulombs. It is suspended at the end of a rine threa 25cm long and placed in a horiztonal electric field. The effect of the field is to move the ball's centre 1.5cm to on side of a vertical line through the point of suspension. What is the force on the tennis ball? What is the magnitutde of the electric field? I'm not even sure how to start this one so any help would be really appreciated!