Figure this out....Newton's 1st law?

Question

A high tech jet car speeds along the desert floor at a constant velocity of 180 miles/hr north. what is the net force on the jet car?

The jet car hits some sand which causes a drag force on the car of 5000 N to the south. The computer instantly compensates so the jet exerts a thrust force on the car of exactly 5000 N to the north at the same time the car hits the sand. The jet car now... choose ALL that apply:
slows down
remains at rest
maintains constant velocity
moves with constant non-zero velocity
speeds up
moves with a changing velocity
accelerates at a constant rate

What happens?

Answer 1

Hi. The car is traveling at a constant speed at first, so the forces cancel. After hitting the sand the forces again instantly balance, so:
maintains constant velocity
moves with constant non-zero velocity

Answer 2

If the velocity is not changing, there is no net force.

If the two 5000N forces are applied in opposite directions simultaneously, there is still no net force, and the car
i) maintains constant velocity
ii) moves with constant non-zero velocity

In the situation you've described, both these are the same thing.