Question

A stone is dropped into a well 45m deep. A sound is heared after 3.13sec after the stone is dropped. Find the speed of stone.(g=10m/s).

Answer 1

Given ;
h = 45 m
u = 0
g = 10
t = ?
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h = ut + 1/2 at^2
45 = 0 + (1/2)×10×t^2
t^2 = 9
t = 3

v^2 - u^2 = 2gh
v^2 = 2×10×45
v = 30 m/s
_______________
distance = 45 m
Time = 3.13-3 = 0.13 sec
speed of sound = v = ?

v = S/t
v = 45/0.13
v = 346.15 m/s
_______________
Hence the speed of the stone is 30m/s and the speed of the sound is 346.15 m/s
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