I have multiple questions like the following and need help on how to work out the answer of one because our book does not cover impulse.

a car is at rest when it experiences a fwd propulsion force to set it in motion. it then experiences a second fwd propulsion force to speed it up more. finally it brakes to a stop.
I=
(change in )P=
Fapp=4000N
at rest P1=0
t=4.0s
P2=

I=
(change in P)=
Fapp=6000N
t=3.0s
P3=

I=
(change in) P=
Ffrict=8000N
t=
Stopped
P4= (I am assuming 0)