stones

a stone is dropped into a well 80m deep & impact of sound is heard after 4.25 s if g=10m/s2 d vel of sound in air is

5 Answers

d ans is 320 m/s

now , u have s=1/2 at²

so 80=1/2 *10*t²

this gives t=4

so this means after the ston e hits the bottom of the well , we get back the echo in 0.25 sec.

this means soound travels 80m in 0.25 sec

so speed of air = 80/0.25 =320 m/s

d particle is being dropped from rest
so,
v²=2as
v²=2.10.80
v=40m/s

now time required to fall is.......v=at
40=10t
t=4s

so for d sound to come...it is 4.25-4 s
i.e. 0.25s

so velocity required is v=s/t
v=80/0.25
v=320m/s

tanx frnds

y r u saying thanks brinda?????Are u by mistake jb6098????

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