Do fired shells maintain momentum?

So here's a question... what happens to shells in WoT when they leave the barrel? Do they maintain the firing tank's momentum in whatever direction it was heading or do they "spawn" in and get a speed vector set for the direction they were fired in?

Let me give an example:

• Hypothesis: 2 tanks; Shell speed = 1000 m/s; Firing distance = 500 m; Tank max speed = 50 kph. You are tank A.

• Scenario 1. Tank A fires at tank B. Tank A is stationary, Tank B is going 50kph at 500m distance perpendicular to A's shot. 50kph = 14 m/s so in order to hit the spot you're aiming at, ignoring RNG, you need to aim 7 meters in front of the point you want to hit.

• Scenario 2: Tank A and Tank B are driving parallel to each other and in the same direction, at the same speed, at 500m distance. Tank A fires at tank B. this is where the question comes in: Does the shell keep the momentum of the firing tank? In which case you would not need to lead the shot at all, you could autoaim, because both tanks travelling at the same speed means they're stationary relative to each other.

Or... in scenario 2, does the shell appear in game with a lateral speed of 0, as if fired by a stationary tank, and thus requires the same amount of lead as in scenario 1?