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Question Number 41962 by Necxx last updated on 16/Aug/18
$${A}\:{student}\:{holding}\:{a}\:\mathrm{324}{Hz}\:{tuning} \\ $$$${fork}\:{approaches}\:{a}\:{wall}\:{at}\:{a}\:{speed} \\ $$$${of}\:\mathrm{6}{ms}^{−\mathrm{1}} .{The}\:{speed}\:{of}\:{sound}\:{in}\:{air} \\ $$$${is}\:\mathrm{336}{ms}^{−\mathrm{1}} .{What}\:{frequency}\:{will} \\ $$$${the}\:{student}\:{detect}\:{from}\:{waves} \\ $$$${omitted}\:{from}\:{the}\:{fork}\:{and}\:{waves} \\ $$$${coming}\:{from}\:{the}\:{wall}? \\ $$
Commented by tanmay.chaudhury50@gmail.com last updated on 16/Aug/18
Answered by tanmay.chaudhury50@gmail.com last updated on 16/Aug/18
$${here}\:{observer}\:{holding}\:{the}\:{tuning}\:{fork}... \\ $$$${that}\:{means}\:{source}\:{of}\:{sound}\:{and}\:{observer} \\ $$$${are}\:{moving}\:{with}\:{same}\:{velocity}... \\ $$$${i}\:{am}\:{trying}\:{to}\:{solve}\:{it}... \\ $$$$\left.\mathrm{1}\right){frequency}\:\mathrm{324}{Hz}\:{will}\:{be}\:{heard}\:{by}\:{the}\:{students} \\ $$$${omittex}\:{from}\:{tuning}\:{fork}... \\ $$$$\left.\mathrm{2}\right){for}\:{second}\:{part}\:{assume}\:{the}\:{reflected}\:{sound} \\ $$$${is}\:{the}\:{source}\:{of}\:{sound}... \\ $$$${taking}\:{reference}\:{from}\:{attached}\:{comments} \\ $$$${f}=\left(\frac{{c}\pm{v}_{{r}} }{{c}\pm{v}_{{s}} }\right){f}_{\mathrm{0}} \\ $$$$\:{f}\:\:=\left(\frac{\mathrm{336}+\mathrm{6}}{\mathrm{336}−\mathrm{6}}\right)\mathrm{324}=\mathrm{335}.\mathrm{78}\approx\mathrm{336} \\ $$$${pls}\:{check}\:{and}\:{comment}... \\ $$
Commented by Necxx last updated on 17/Aug/18
$${yes}\:{sir}.{This}\:{is}\:{the}\:{answer}.{Thank} \\ $$$${you}\:{for}\:{your}\:{help}\:{at}\:{all}\:{times}. \\ $$