One of my least favorite IB topics. Nothing to do but jump in with both feet…
Parallel & Coincident Lines
Parallel Lines - Angle between the lines is zero.
Coincident Lines - Same line or two lines that lie on top of one another
Perpendicular Lines - have an angle of 90 degrees between them
Occasionally the IB will ask you to write a "Cartesian equation" from a vector equation of a line. This is often done to help you with finding intersection points and such.
It is very common for the IB to ask at what point two lines intersect or IF they intersect.
Collisions - More Than Just Intersecting
Collisions are a half step up in difficulty from intersection points as we now have to consider time as well.