Experimental evaluation of the drag coefficient of water rockets by a simple free-fall test

摘要: The flight trajectory of a water rocket can be reasonably calculated if the magnitude drag coefficient is known. experimental determination this with enough precision usually quite difficult, but in paper we propose simple free-fall experiment for undergraduate students to estimate rockets made from plastic soft drink bottles. performed using relatively small fall distances (only about 14 m) addition digital-sound-recording device. time inferred recorded signal good precision, and it subsequently introduced as an input Matlab® program that estimates coefficient. This procedure was tested first toy ball, obtaining result deviation typical sphere value only 3%. For particular used present investigation, 0.345 estimated.