a construction workers helmet slips and falls when he is 78.4m above the ground he hears the sound of the helmet hitting the ground 4.23seconds after it slipped find the speed of sound on air

Asked by pragathi smart tutorials pragathi smart tutorials | 6th May, 2012, 07:47: PM

Expert Answer:

we can divide the jouney in two parts.
1.the stone will first fall through 78.4 m say it will take t1 s and
2. then sound will be produced and the sound will come and travel 78.4 m and come to his ear say in t2 s.
 
h=78.4 m
for the stone, 1/2 gt12=78.4
t1=4 s
t2=0.23s
vt2=78.4
v=340 m/s approx
 

Answered by  | 8th May, 2012, 11:37: AM

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