[题目]三个质量相等的物体A、B、C紧靠在一-|||-起,置于光滑水平面上,如图。若A、C分别受到-|||-水平力F1、 _(2)((F)_(1)gt (F)_(2)) 的作用,则A对B的作用力-|||-大小为 ()-|||-A.F1-|||-B. _(1)-(F)_(2)-|||-C. dfrac (2)(3)(F)_(1)+dfrac (1)(3)(F)_(2)-|||-D. dfrac (2)(3)(F)_(1)-dfrac (1)(3)(F)_(2)-|||-E. dfrac (1)(3)(F)_(1)+dfrac (2)(3)(F)_(2)-|||-F. dfrac (1)(3)(F)_(1)-dfrac (2)(3)(F)_(2)