There are several information's already given in the question. The answer can be easily deduced using those information's.
Time = 3.0 * 10-3 seconds
Impulse = 0.30 newton
Then
Force = Impulse/Time
= 0.30/3.0 * 10-3
= 1 * 10^3 newtons.
I hope the above procedure is clear for you to understand and it has actually come to your great help.
