A) 225 m/s
B) 340 m/s
C) 510 m/s
D) 1020 m/s
Correct Answer: B
Solution :
Key Idea: Time taken by echo to reach the person is directly proportional to distance. Let distance of person from hill A be x meter, then from hill B is (510-x)m. \[\therefore \] \[\frac{x}{510-x}=\frac{{{\left( time \right)}_{1}}}{{{\left( time \right)}_{2}}}=\frac{1}{2}\] \[\Rightarrow \] \[x=170\,\,m\] Time taken for the echo to travel 170 m is given by \[\frac{1}{2}=0.5\,s.\] \[\therefore \] \[\text{Velocity}=\frac{\text{distance}}{\text{time}}=\frac{170}{0.5}=340\,\,m/s\]You need to login to perform this action.
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