Did you hear that?
Classical Mechanics
Level
2
A boy standing in front of a cliff on the other side of a river explodes a powerful cracker. He hears an echo after 4 seconds. Then he moves \(125\text{ m}\) backwards and again explodes another powerful cracker. This time, he hears an echo after 5 seconds. Calculate the width of the river (in metres).
by
Ashish Siva