Given two disks D1 and D2. Their radii, positions, and velocities are known. How can I predict whether they will collide or not? For a head-on collision, the angles that the directions of motion make with the x-axis add up to 180 degrees. But I don't know what is the condition for an oblique collision. Any help would be appreciated.
Given the velocities and positions, first consider the two bodies to be point objects and find the distance of closest approach between the two points (centers). If this distance ($d_c$) is zero, then they collide head-on, if $d_c <r_1+r_2$, then they will collide, or else they won't collide.