Please answer this, show your solutions in paper.I will give you a very good feedback. Thank you!In paper please :(

3. Two charges of +10 - C are located 1 cm apart. (a) What is the force on a charge +10 - C halfway between them? (b) What is the force on a charge of -10 - $ Cat the same place? 4. At the corners of a rectangle ABCD of sides 8 cm. and 6 cm are charges of +50, -30, +20 and -40, all in C, respectively. AB is the longer side and BC is the shorter side. Findthe force on a +15 /C charge placed at the center of the rectangle