Question

If a hole is bored along the diameter of the earth and a stone is dropped into hole

• A. The stone reaches the centre of the earth and stops there
• B. The stone reaches the other side of the earth and stops there
• C. The stone executes simple harmonic motion about the centre of the earth
• D. The stone reaches the other side of the earth and escapes into space

Answer 1

Answer: (C)

The stone executes simple harmonic motion about the centre of the earth

Answer 2

The stone execute S.H.M. about centre of earth with time period $T = 2\pi\sqrt{\frac{R}{g}};$ where R = Radius of earth.