Answer:
I = -3.89 104 N s
Explanation:
The impulse has two expressions on the one hand is equal to the product of force by time and on the other is equal to the moment variation of the system
I = ∫ F dt = Δp
Note that if the initial positive velocity the final one that has the opposite direction must be negative
Let's replace and calculate
I = mvf -mvo
I = 1692 (-3) - 1692 (20)
I = -3.89 104 N s
[N s ] = [ kg m/s² s] = [ kg m/s]