Physics I Static Electricity Question!?

Any help would be much appreciated! I just can't seem to figure these out:





1. A 9.00 V battery is connected between 2 parallel metal plates 4.00 mm apart. What is the magnitude of the electric field between the plates and what would happen to the electric field magnitude if the distance between the plates were doubled?





2. A proton moves 25 cm on a path parallel to the direction of a uniform electric field 5.00 N/C x(hat) What is the change in electrical potential energy of the proton? What if the particle were an electron instead? Would it move in the same direction and what would happen to the potential energy of the electron?





3. Particle A, charge -2.30x10^-6 C, is placed at the origin of a coordinate system. Particle B, charge 4.60x10^-6 is fixed at x=0.00m, y=.120m above particle A. Particle C, charbe -2.30x10^-6, is fixed at x=.240m, y=0.00m to the right of particle A. Find dthe net force on particle A in component and in magnitude angle forms.





thanks so much!