A stone weight 100N on the surface of earth. The ratio of its weight a...
Solution:
We know that the weight of an object is given by the formula:
Weight = mass x acceleration due to gravity
Where acceleration due to gravity (g) is given by:
g = G x M / r^2
where G is the universal gravitational constant, M is the mass of the earth, and r is the distance from the center of the earth.
Weight at the surface of the earth:
Weight of the stone at the surface of the earth is given as 100N.
Weight at half the radius of the earth:
At a height of half the radius of the earth, the distance from the center of the earth is r/2. Therefore, acceleration due to gravity at this height is given by:
g' = G x M / (r/2)^2 = 4 x G x M / r^2
Weight of the stone at this height is given by:
Weight' = mass x g'
Since mass is constant, we can write:
Weight' / Weight = g' / g
Substituting the values of g and g', we get:
Weight' / Weight = 4
Therefore, weight of the stone at half the radius of the earth is 4 times its weight at the surface of the earth.
Weight at a depth of half the radius of the earth:
At a depth of half the radius of the earth, the distance from the center of the earth is 3r/2. Therefore, acceleration due to gravity at this depth is given by:
g'' = G x M / (3r/2)^2 = 4/9 x G x M / r^2
Weight of the stone at this depth is given by:
Weight'' = mass x g''
Since mass is constant, we can write:
Weight'' / Weight = g'' / g
Substituting the values of g and g'', we get:
Weight'' / Weight = 4/9
Therefore, weight of the stone at a depth of half the radius of the earth is 4/9 times its weight at the surface of the earth.
Ratio of weight at half the radius to depth of half the radius:
Weight' / Weight'' = (g' / g) / (g'' / g) = (g' / g) x (g / g'') = 4 x (9/4) = 9
Therefore, the ratio of weight of the stone at half the radius of the earth to its weight at a depth of half the radius of the earth is approximately 9.
Hence, the answer is option D) 0.9.
A stone weight 100N on the surface of earth. The ratio of its weight a...
3.6
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