A Boy Stand At A Certain Distance From A Large Building And Blow A Whitle After 2.3s He Hear It Echo.He Move 50m Toward The Building And Blow He Whitle Again, This Time It Echo Reach Him After 2.0s.Calculate The(1)boy Original Distance From The Building (2)the Speed Of Sound In Air?

Answer 1

distanceofecho=2*distancefrombuilding
distanceofecho=vsound*time
so between the two echos...
50*2=vsound(2.3-2.0)
vsound=100m/.3sec=333 m/s

Answer 2

1. r *( 2.3/2) = d,
r = 0.87d.
r *( 2/2) = d-50,
Replace r with 0.87d:
0.87d * 1 = d-50,
d = 384.6 m.

2. r = 0.87d = 0.87 * 384.6 = 335 m/s.= Speed of sound.