$12.1 mechanical waves Wavefronts-the surfaces on them all the points are in the same state of motion Wave ray--the direction which are perpendicular to the wavefronts or parallel to the velocity of the waves Ray Ra $12.1 mechanical waves According to the shape of the wavefronts Plane waves: the wavefronts are plane Cylindrical wave: the wavefronts are cylindrical Spherical wave: the wavefronts are spherical3 Wavefronts—the surfaces on them all the points are in the same state of motion. Wave ray—the direction which are perpendicular to the wavefronts or parallel to the velocity of the waves §12.1 mechanical waves According to the shape of the wavefronts Plane waves: the wavefronts are plane Cylindrical wave: the wavefronts are cylindrical Spherical wave: the wavefronts are spherical §12.1 mechanical waves