IIT JEE , AIEEE Forum - Physics , Mechanics

hardcore_genius

If a tunnel is dug across the diameter of the earth & an evacuated box containing a pendulum is dropped into it,how will the time period of pendulum changes????????

Betu

The pendulum's period depends upon g , apart from its length.

since g doesn't vary inside the earth (!!!!.) and length is constant, the period of pendulum will remain constant.

if satisfied, pl rate me !!!!!!!

spideyunlimited

let r be the distance of bob from earth's centre and R be radius of earth
while bob is on surface of earth , g will be GM/r^2
while bob is inside earth, g will be GMr/R^3

spideyunlimited

first time period of pendulum will keep on increasing till it reaches the centre of earth, where g becomes 0 , then due to the box's attained velocity it moves further across the diameter where its time period starts decreasing.. and finally 2 pi root(l/g).. then it will go back again to the centre.. same process keeps on repeating.

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