Answer
The magnitude of the total momentum of the system is 0.
Work Step by Step
Let the mass of each car be $m$.
Let $v_1 = 19~m/s$ be the velocity of one car.
Then $v_2 = -19~m/s$ is the velocity of the other car.
We can find the total momentum of the system:
$m~v_1+m~v_2 = (1300~kg)~(19~m/s)+(1300~kg)~(-19~m/s) = 0$
The magnitude of the total momentum of the system is 0.
