A truck blowing horn of frequency 500Hz travels towards a vertical mountain and driver hears echo of frequency 600Hz. If velocity of sound in air is 340m//s then speed of truck is

A truck blowing horn of frequency 500Hz travels towards a vertical mou

1.	A truck blowing horn of frequency 500Hz travels towards a vertical mountain and driver hears echo of frequency 600Hz. If velocity of sound in air is 340m//s then speed of truck is
Answer» `31m//s` `41m//s` `51m//s` `21m//s` SOLUTION : The sound REFLECTED from mountain appears to be coming from mirror of SOURCE. Thus image appears to be moving TOWARDS the vehicle (DRIVER) `v_(0)=v_(s)=x :.n.=n((V+V_(0))/(V-V_(s)))` `:.(l_("air"))/(l_("water"))=sqrt((T_("air"))/(T_("water")))`