Displacement time graph of particle moving in a straight line is as shown in figure.

From the graph we can conclude that work done on the block is :

Slope of the graph at a point = velocity,$t_1=0$ to $t_1$velocity increases.

$t_1$to $t_2$ velocity decreases, $t_2$ to $t_3$ velocity zero and ${\mathrm{t}}_3$ to ${\mathrm{t}}_4$ velocity is constant.