Which is faster the speed of sound or the touch sense?
Nerve signal transmission speed varies widely depending on the type of nerve and the type of signal. Pain signals move surprisingly slowly, while pressure-sensing moves quickly (so, in your example, you’d feel the pressure of the slap before the pain). The pressure-sense travels at (roughly) 170mph, and the pain signal at around 1.5 mph. Sound, at sea-level air-pressure, travels at about 770 mph (so about 4.5 times the speed of pressure-sensation, and over 500 times faster than pain-sensation). So the sound would reach your ears faster than the nerve impulses would reach your brain. But remember that your ears transform this sound into nerve-signals too (and these signals are quite fast – travelling at about 240 mph). All things considered, the person you slapped would probably hear it first, feel the pressure shortly afterwards, and then the pain would come last.
