Fixed Velocity - Sticking Together

It appears that in the fixed velocity implementation, ants are getting stuck together. This may be the result of not conserving momentum but using readings from conservation of momentum... perhaps the ants aren't really stuck but they are now headed in the same direction. Definitely worth investigating.

No file or test is named in the issue. Locate the fixed velocity implementation, reproduce the ants-sticking behavior, and compare its momentum-related calculations with the surrounding simulation logic. Done means the behavior is explained and the implementation no longer incorrectly causes ants to remain together, with a regression check if the project has an applicable test path.

Written by the indexing model from the issue text.