Hi, I have a question about a basic principle of physics: the laws of motion. If two identical buses were traveling towards each other at a speed of 40 mph, assuming a lot of things are constant, their resulting motion in either direction would be 0, correct? Is this principle the same for every state of matter that collides with an equal but opposite force, like liquids, gases, or plasmas? Or do different states of matter cause more varied outcomes than two solid objects running into each other? For instance, if two identical water waves were to collide, would the net result be 0 as quickly and as definitively as with two solids? In that vein, would two really hot pressure waves traveling towards each other head on, would this outcome be any different than two solid objects, like buses, colliding? Is there a larger amount of "slippage" or "fluidity" of the molecules in different states of matter like liquids or gases than in solids, which causes them to behave differently (in the short term) than two solids colliding? One more example, if you could play the exact same song out of two speakers facing each other, if they collided midway, would the resulting motion of the two sound waves then be stopped? Thanks!!!