I'm having trouble wrapping my head around problems without any given number values. All of the book problems I've done so far have had number values for position or velocity etc and those fit nicely into equations that could be solved for other variables. I was recently given a set of sample quiz questions and they are all like this: 1. An object moving along the x axis has a constant negative acceleration of a1 and an initial velocity of +v1. A second object located +d meters ahead of the first one also has a constant acceleration of +a2 with an initial velocity if +v2. Find the condition(s) on v1 and v2 such that a collision will not occur. How would I go about solving something like this?