b) What frequencies do Charlie and Colby hear at the instant when Colby catches the tennis ball? c) What frequencies do Charlie and Colby hear at the instant when the tennis ball is at the highest point above the the ground? d) Discuss qualitatively [that is, without numerical calculations] the time-dependent frequency observed by Charlie and Colby! . 3 as = 1.) Charlie and Colby are best pals who stand at the distance D = 23.6 m from each other on level ground. Charlie throws the ball from a height above ground Ho 1.2m; the ball reaches the maximum height Hmax = 5.5 m above ground; Colby catches the ball at the same height Ho. The tennis ball undergoes projectile motion - ignore effects of air resistance. The tennis ball is equipped with a device that makes a sound with frequency 493.88 Hz [the musical tone "B" in the fourth octave]. Speed of sound in air sound = 343 m/s. The ears of Charlie and Colby are also at the same height Ho. a) What frequencies do Charlie and Colby hear at the instant when Charlie throws the tennis ball?