Question

the diameter and the thickness of a hollow metals sphere are 12 cm and 0.01 m respectively. the density of the metal is 8.88 gm per centimetre cube. find outer surface area and the mass of the sphere?

Answer 1

Diameter of sphere from outside = 12 cm

Radius from outside R = 6 cm

Surface area = 4 πR²

= 4 (22/7) (6²) = 452.57 cm²

Now, Thickness of sphere = 0.01 m = 1 cm

Diameter from inside = 12 - 2 = 10 cm [ -2 is done to reduce from both sides ]

Radius from inside r = 5 cm

Volume of this sphere V = Volume of outside sphere - Volume of inside sphere

So, V = 4/3 πR³ - 4/3 πr³ = 4/3 π (R³ - r³)

V = 4/3 (22/7) (6³ - 5³)

V = 4/3 (22/7) (91)

V = 381.33 cm³

Now, Density = Mass / Volume

Mass = Density x Volume

Mass = (8.88) x (381.33)

Mass = 3386.24 g = 3.38624 kg

Answer 2

Answer:

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