Answer
F2 = (0N) i
Work Step by Step
The box is 2kg. We are shown F1 is acting towards the right along the x axis and that it has a magnitude of 20N. In part a, we are told that ax = 10$m/s^2$. Since F = ma then the Force = 2kg * 10 $m/s^2$ = 20N. Since F1 is already 20N, then F2 = 0
