On earth, the weight of a particular object is w at the surface. Assuming the earth radius to be r and mass to be m, what is the weight of the object at a point 3r from centre of earth?
What is the weight of the object on the surface of another planet radius 4r and mass 2m?
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Answer:
At a point 3r from centre of earth:
F = GMm/r² = w
As we can see, w is proportional to 1/r²
Hence, at a point 3r from earth, the weight will be w/9
On the surface of another planet radius 4r and mass 2m:
F = GM(2m)/(4r)²
= (GMm/r²) / 8
= w/8
Hence, weight of object = w/8
