Proper velocity Proper velocity In relativity, proper velocity, also known as celerity, is an alternative to velocity for measuring motion. Whereas velocity relative to an observer is distance per unit time where both distance and time are measured by the observer, proper velocity relative to an observer divides observer-measured distance by the time elapsed on the clocks of the traveling object. Proper velocity equals velocity at low speeds. Proper velocity at high speeds, moreover, retains many of the properties that velocity loses in relativity compared with Newtonian theory. For example, proper velocity equals momentum per unit mass at any speed, and therefore
This Is What Rock n' Roll Looks Like depth about the genre mix in "This Is What Rock n' Roll Looks Like": Although the song's title references the physical appearance of what rock and roll looks like, Porcelain Black revealed in an interview with AOL's "NoiceCreep" that rock and roll is not dependent on the physical appearance of someone. She stated: "This Is What Rock n' Roll Looks Like" received generally mixed reviews by critics, most of whom were surprised with Porcelain Black's outgoing persona and the pop production by RedOne. Gerrick D. Kennedy of "Los Angeles Times" complimented the song's production by stating that it could have