Kinematics - what does it mean mathematically when 2 objects meet midair? I faced a problem in kinematics where I got some data about 2 objects (doesn't matter the actual data ) but I have been told an important detail.

The 2 objects meet midair

The thing is that I don't understand what does it means mathematically, does it mean that the equation of the position over time of the first object is equal to the equation of the position over time of the second object?
Thank you
 A: It is obvious that two objects that have spatial extent cannot occupy the exact same location. So when it is stated The 2 objects meet midair this does not mean they occupy the same volume in the same instant, unless the objects are point particles.
But the answer is yes, if we consider two objects to be point particles with no dimensions. If they meet then at some instant they are coincident, or exist at the same point in space at the same time (or in relativity, at the same point in spacetime).
If we have equations that describe the positions of the objects as a function of time, $x_1(t)$ and $x_2(t)$, then if at a certain time $t'$ the objects meet, then $$x_1(t')=x_2(t')$$
A lot of time you will see problems that for example, ask at what time will both objects be located at $x=$ etc. This does not mean that at some time will they both occupy a similar volume. It means that both objects will have some path, and if you graphed both paths, the point(s) of intersection of these paths is where they "meet". Or think about both particles colliding at some point $(x',t')$ where their contact surface points are located at $(x',t')$ (their boundaries are coincident) rather than both objects.
A: It typically means the objects collide with each other while moving in air.  For objects not considered as point masses their center of masses are not at the same position during impact, but the surfaces of the objects come into contact and exert forces on each other (equal and opposite if Newton's third law holds which is true for collisions in classical dynamics).  The motions of the objects after the collision depends on the angle of impact (head on or glancing) and whether the objects are inelastic or elastic.
