Refinement of the discharge notation

I have found that there are a few nuances to the behavior behind the movement of objects within a plane that have hindered my ability to come to conclusion with what the valid approach would be for finding the loss of a displacement-based vector. Luckily, I've came to understand these rules of abrupt vector loss.

The loss of a vector, that acts like velocity, can be found by directly using the distance/length traveled by the vector's user. (the mass would be for velocity) But the more well-tested approach is using the initial magnitude of the vector alongside the time taken to reach the distance/length.
Extrapolation is used when finding the X amount lost with a set amount of time after there's decrease/deceleration acting on the vector.