In older times, people used to think that the Earth was flat. Imagine that the Earth is indeed not a sphere of radius r, but an infinite plate of thickness H. What value of H is needed to allow the same gravitational acceleration to be experienced as on the surface of the actual Earth ? (Assume that the Earth's density is uniform and equal in the two models).

Options

A. `(2R)/(3)`
B. `(4R)/(3)`
C. `(8R)/(3)`
D. `(R )/(3)`

Answer

A

Explanation

`G(4)/(3)pi rho R = (4pi G rho H)/(2)`