How are both electromagnetic and mechanical waves used when people communicate with each other?

Unlike mechanical waves, which require matter, electromagnetic waves can travel through empty space, as well as through liquids, solids, and gases. There are many similarities between light waves and mechanical waves. They can both be measured by their amplitude, wavelength, and frequency.

I'm not sure what your asking buddy.. but i know that you can weld two peices of steel by pure force and pressure.