The weight of a body on the surface of the earth is 100 N. The gravitational force on it when taken at a height, from the surface of earth, equal to one-fourth the radius of the earth is:
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Question

The weight of a body on the surface of the earth is 100 N. The gravitational force on it when taken at a height, from the surface of earth, equal to one-fourth the radius of the earth is:

G1 Physics · Accepted Answer

At height h above Earth's surface, g(h) = g[R/(R+h)]² Here, h = R/4 So, g(h)/g = [R/(5R/4)]² = (4/5)² = 16/25 Weight at height h: W(h) = 100 × 16/25 = 64 N Hence option A follows.