Sound waves travel at the rate of 343 m/s at 20°C. If a man standing 450 meters away from the wall of a canyon yells, “Hello,” how long will it take for him to hear his own voice echo off of the wall?

2.62seconds

Explanation:

Echo occurs when sound reflects and causing a delay before getting to the listener.

Let x be the distance from between the source and the reflector

t be the time taken for the echo to occur

v be the velocity of sound in air.

Using the relationship 2x = vt

t = 2x/v

Given x = 450metres

v = 343m/s

t = 2(450)/343

t = 900/343

t = 2.62seconds

It will take 2.62 seconds for him to hear his own voice echo off of the wall.

explanation:

considering the bohr theory, the type of connection that requires the transfer the answer conuldn't be right

talk back to him about the sport and show him your expertise or leave the room