Longitudinal wave and seismic P-waves (created by earthquakes and explosions). In longitudinal waves, the displacement of the medium is parallel to the propagation of the wave, and waves can be either straight or round. A wave along the length of a stretched Slinky toy, where the distance between coils increases and decreases, is a good visualization. In the case of longitudinal harmonic sound waves, the frequency and wavelength can be described by the formula where: The quantity "x"/"c" is the time that the wave takes to travel the distance "x". The ordinary frequency ("f") of the wave is given by The wavelength
The Crests was born and where he began his music career, introduced an Extension of Remarks in the House of Representatives. This posthumous honor is now a permanent part of the Congressional Record. The Extension of Remarks includes the original members of The Crests. On November 12, 2013, J.T. Carter was honored by the Pennsylvania State House, Speaker of the House Sam Smith, and PA State Representative Rosemary M Brown, for his lifetime in the music industry and for being the first African American to form an interracial vocal group in the America. Carter was officially recognized on the state house floor.