Minecarts have a higher average velocity with a passenger compared to without

Minecarts with a passenger (Player or other entity) travel at faster velocities than an empty minecart.

Steps to reproduce:

1. Run /gamerule minecartMaxSpeed 1000 to exaggerate the effect
2. Create a line and then a ramp of powered rails
3. Destroy the highest flat rail, leaving the last powered rail diagonal
4. At the start of the line, create a one block high ramp
5. Place a minecart on the start ramp so that it immediately begins moving
6. Repeat the previous step but place an entity inside of the rail before you place the minecart, or hop in the minecart without pressing the forward button

Screenshot:

Green dots represent the trajectory of a player in the minecart
Yellow asterisks represent the trajectory of a tamed, sitting wolf in the minecart
Red circles represent the trajectory of an empty minecart