This question is the first of a series about specific use of teleportation. It will concern only about momemtum and speed: other subjects will be exposed later.
The story happens in our world and current era. The protagonist possesses the power of teleportation with the following characteristics:
- When teleporting, a volume including the protagonist is swapped with the same volume of matter in another place. For example, if the destination is in open air, the departure will receive the same volume of air.
- That result with no problem of collision of matter: if the destination is in a solid rock, the protagonist will arrive in the rock. And at the departure, there will be a volume of rock with the same shape as the protagonist.
- There are no collision problems, but there are still problems: the destination can override a part of something since what matters is the volume. It’s not a problem when swapping a part of a rock, but it’s one when swapping a part of a person.
- The volume of exchange has the same shape as the protagonist adding a layer around it. The layer is at minima 5cm, but can expand by willpower.
- There is no minimum time between two swaps: it can be as short as reflexes permits.
- The protagonist can teleport as long as it has willpower: think of it as a superhero power.
- The teleportation happens if the protagonist can picture it. Coordinate won’t work, but a memory, a picture/film will (no matter the distance). The protagonist could also teleport in a hidden part, even if what behind is unknown as long as the protagonist can guess it (for example behind a door or a rock).
- Both volume exchanged keep their momentum ignoring the difference in velocity of the Earth's rotation. Falling toward Earth on the south pole, and teleporting to the north pole will result in the protagonist still falling. Flying westward and teleporting to facing eastward, will cause the protagonist to shoot forward in the eastward direction at the same speed.
- If the destination is a moving structure (vehicle...), the protagonist will teleport at the coordinate where the structure was when teleporting. But the protagonist will keep its momentum, resulting in a possible speed difference. Comparison is like trying to jump in a car in your everiday life: there won't be too much problems if the car is slow or stopped, but there will if you are on foot and the car is at 90km/h. -If the destination is a picture or a memory of a moving structure, the destination will be at the coordinate when the picture/memory took place.
As the title said, my question is about that last point: speed.
Are they possible downside with keeping momentum when teleporting?
The two major problems I could find are:
- Teleporting in a moving object when motionless or vice versa.
- Teleporting by accident above a pit resulting in a free fall, which another teleport won’t resolve (unless quick thinking).
Please try to not raise problems from other subject since there will be other questions for them.
Edit: see also the answer of Zeiss Ikon, which is a nice one.