Answer
See the detailed answer below.
Work Step by Step
a) See the figures below, and recall that: $F_n\rightarrow$ Normal force. $F_G\rightarrow$ Gravitational force (the weight of the object). $f_k\rightarrow$ Kinetic friction force. $F_{sp}\rightarrow$ Spring force.
b) The acceleration here is directed to the right since the net force is in the positive $ x$-direction.
c) The direction of the speed is toward the spring force, as we see in the figure below, which means toward the right.
The object is speeding up in the positive $ x$-direction.
d) A box was attached to a spring that was initially compressed and then left free. The spring pushes the box to the right. The box is moving on a rough flat horizontal surface.
