I am studying for my exam for physics and i came across 2 questions that i sort of need help with. 1. Two identical spheres, with charges of Qa=-2Q and Qb=1Q, attract one another with a force of 9.0 x 10^-4 N. A third identical uncharged sphere C touches B and now C is completely removed from this situation. Finally, the two spheres (A and B) are touched together and move a distance of 2R apart. What is the new force? I solve this ratio questions using the mx method but thats not my biggest problem. I don't know how to determine the charges of the 2 spheres. Can anyone please help me. I know the charges for both are supposed to be 3/4 for both. But is there a method to determining the charges. 2. A person swims 50 m[E], then 60 m[N40W], then 70 m[S60W], and finally 100 m [W30N]. Determine the resultant displacement. Some of these angles arent the angle to the horizontal but i get confused, so can you tell me which angles are the angles to the vertical. Are the ones with angles to the vertical only the 60 m and 70 m because when i draw the 70 m vector the angle seems right, but it cant be right can it? So please i really need help.