posted by Tiffany .
Two horizontal forces, F1 and F2, are acting on a box, but only F1 is shown in the drawing. F2 can point either to the right or to the left. The box moves only along the x axis. There is no friction between the box and the surface. Suppose that = +6.2 N and the mass of the box is 3.3 kg. Find the magnitude and direction of when the acceleration of the box is (a) +5.5 m/s2, (b) -5.5 m/s2, and (c) 0 m /s2.