when force is applied towards right then acceleration is, a = F/m
i.e., a = 10/2 = 5 m/s2
Similarly, when force is applied towards left then acceleration is
a = 5/2 = 2.5 m/s2
which means there is an acceleration of 2.5 m/s2 towards right.
(i) For acceleration of 1 m/s2 towards left, the force applied towards right should be of 3 N
and, (ii) For acceleration of 1 m/s2 towards right the force applied towards left should become 8 N.