From the graph, it is clear that upto $t=2.0\, s$,
the body moves with a constant velocity
Slope of position-time graph $=\frac{4}{2}=2\, m / s$
After $t=2.0\, s$, position-time graph is parallel to time axis which means that body comes to rest.
$\therefore $ Change in velocity $=d v=2\, m / s$
Impulse $=$ Change in momentum
$=d p=m d v=0.1 \times 2=0.2 \,kg - m / s$
