A construction worker's helmet slips and falls when he is 78.4 m above the ground. He hears the
sound of the helmet hitting the ground 4.23 seconds after it slipped. Find the speed of sound in air.
Give correct answer ✅✅
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A construction worker's helmet slips and falls when he is 78.4 m above the ground. He hears the
sound of the helmet hitting the ground 4.23 seconds after it slipped. Find the speed of sound in air.
Give correct answer ✅✅
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h = 78.4 m
g = 9.81 m/s2
u = Initial speed = 0
Time taken to hear the sound = τ = 4.23 sec
a) Speed of helmet (v = ?)
Use kinematics engine (free fall)
v ^2 = u ^2 + 2gh
= 0 + 2gh
V=√2gh
V=39.22m/s
Time taken by helmet to reach the ground is t = ?
Use kinematics egh.
v = u + gt
t=39.22/9.81
hence t=3.99s
hence time difference is 4.23-3.99=0.24s
speed of sound in air is =78.4/0.24=326.67m/s
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