Action and reaction forces act on

$A$ bullet of mass $10\,g$ leaves the barrel of a gun with a velocity of $600\,m/s$. If the barrel of the gun is $50\,cm$ long and the mass of the gun is $3\,kg$,then the value of the impulse supplied to the gun will be $.....\,Ns$.

The figure below shows the position-time graph of a body of mass $0.04 \; kg$. Suggest a suitable physical context for this motion. What is the time between two consecutive impulses received by the body? What is the magnitude of each impulse?

$A$ body of $2\, kg$ has an initial speed of $5\, ms^{-1}$. $A$ force acts on it for some time in the direction of motion. The force-time graph is shown in the figure. Find the final speed of the body in $ms^{-1}$.

Figures $I, II, III$ and $IV$ depict the variation of force with time. In which of these situations is the impulse the highest?

The unit of impulse is