19almost an universally known thing :
shm.....with time period of 84.6 minutes !
If a tunnel was dug from one end of the Earth to the other end through the centre of the Earth and a ball would have been relesed in the tunnel at one end , What would have been the ball's motion?Why?
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UP 0 DOWN 0 0 2
2 Answers
106Using equivalent Gauss Law for gravitation,
Let the distance of the ball from the centre of the earth be x Let the mass density of the earth be uniform
Then ∫EdS = 4∩Gmin
As E is symmetrical,
E*4∩x2 = 4∩G*Ï*4/3 ∩x3
=> E = 4∩GÏx/3 = a
So as a = -kx (using vectorial relation)
so the motion is SHM with amplitude equal to the radius of the earth
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