What is the speed of the insect?

1) A bat flying at 4.00 m/s is chasing an insect flying in the samedirection. If the bat emits a 40.0-kHz chirp and receives back an echoat 40.4 kHz, what is the speed of the insect? (Take the speed of soundin air to be 340 m/s.)2) The acoustical system shown in the figure below is driven by aspeaker emitting sound of frequency 732 Hz. (Take the speed of sound as345 m/s.)Image: http://www.webassign.net/sercp8/14-14.gif(a) If constructive interference occurs at a particular instant, by whatminimum amount should the path length in the upper U-shaped tube beincreased so that destructive interference occurs instead?(b) What minimum increase in the original length of the upper tube willagain result in constructive interference?