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A wooden roller is 1 m long and 8 cm in diameter. Find it's mass in grams if 1cm³ of the wood has a mass of 0.7 g​

User Ricardkelly
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1 Answer

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27 votes

Answer:

1120π grams

==> 3518.58 grams using value of π = 3.14159 or

==> 3520 grams using value of π = 22/7

Explanation:

Volume of a cylinder = πr²l where r is the radius of the base and h is the length of cylinder

The diameter of the cylinder, d = 8cm and radius = d/2 = 4cm

Length = 1 meter = 100 cm

Here, volume V = π.4².100 = π x 16 x 100 = 1600π cm³

Since 1 cm³ has a mass of 0.7gm total mass
M = 0.7V = (0.7)1600π =1120π gm


Using the ratio 22/7 for pi we get
M = 1120 x 22/7 = 3520 g

If we use the more accurate value of π as 3.14159 then we get
M = 1120 x 3.14.159 = 3518.58 g which is more accurate

User Sen Alexandru
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