The cars lock together immediately after the collision and only separate later so they have the same final velocity immediately after the collision, we’ll call it . Sticky collisions like this are kno...The cars lock together immediately after the collision and only separate later so they have the same final velocity immediately after the collision, we’ll call it . Sticky collisions like this are known as perfectly inelastic collisions and for such collisions we can treat the objects moving together as a single object that has their combined total mass.
