Answer:
impulse = 8820 kg·
 or 8820 N·s
 or 8820 N·s
Step-by-step explanation:
Impulse J is equal to the average force 
 multiplied by the elapsed time Δt or in equation form, J =
 multiplied by the elapsed time Δt or in equation form, J = 
 Δt
Δt
As long as your force of 450 N is constant then that value is your average force 
 and your elapsed time is 19.4 seconds.
 and your elapsed time is 19.4 seconds.
Multiply these values.
You will get an impulse of 8820 kg·
 or 8820 N·s.
 or 8820 N·s.