2.The surface area of a hollow matal sphere is 400π cm2, the thickness of its metal part is 2cm.
a)find the volume of the metal requized to make the sphere(give your answer in terms of π)
b)If the weight for 1cm3 of metal is 9g, find the weight of the metal sphere.
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2007-02-14 2:14 am
回答 (1)
2007-02-14 2:31 am
✔ 最佳答案
2a. Let r cm be the radius of the sphere.4(pi) r^2 = 400 pi
r = 10cm.
the volume of the metal
= volume of out-sphere - volume of inner-sphere
= 4/3 * pi * (10)^3 - 4/3 * pi * (8)^3
= 1952/3 * pi cm^3
b) the weight = volume of metal * density
= 1952/3 * pi * 9gram
= 5856*pi gram
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