I don't understand why you would need an "infinite" amount of force to push something faster than its speed of sound. If I have a rod with a low sound speed material, and I impact the back of it with a much harder, much more massive object moving at a speed, V, much greater than the rod's sound...
I'm just trying to get a better grasp on sound waves and shock waves.
Let's say I have a cylindrical rod of length L with no forces acting on it, and I push on the back of it with some constant velocity less than the speed of sound, c, of the material the rod is made of. Will the front of the...