Various types of mechanical waves are :

1. electromagnetic, longitudinal, transverse
2. electromagnetic, transverse
3. longitudinal, transverse
4. electromagnetic, transverse.

Due to vibrations of medium particles, the energy transformation is from :

1. heat energy to kinetic energy and vice versa
2. kinetic energy to potential energy and vice versa
3. heat energy to potential energy and vice versa
4. potential energy to nuclear energy and vice versa