The impulse exerted by a force F on an object in a time [tex]\Delta t[/tex] is given by
[tex]I = F \Delta t[/tex]
In our problem, we have a force of 120 N: F=120 N, applied to the baseball for a time of [tex]\Delta t=0.04 s[/tex]. Therefore the impulse is
[tex]I=F \Delta t = (120 N)(0.04 s)=4.8 Ns[/tex]