this is a question of chapter mensuration
Answers
Answer : 246.4 kg
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Given,
A cylindrical roller is 2m long. Inner diameter is 35 cm and thickness is 7 cm all around.
To find :
Find the weight of roller in kg if 1 cm³ of iron weighs 8 g.
Solution :
Height of cylindrical roller = 2m = 2 * 100 = 200 cm
Inner diameter = 35 cm
∴ Inner radius, r₁ = 35/2 = 17.5 cm
Outer diameter = 35 + 7 = 42 cm
∴ Outer radius, r₂ = 42/2 = 21 cm
Now,
⇒ Volume of cylinder = πr²h
⇒ Volume of cylindrical roller = π(r₂² - r₁²)h
⇒ Volume of cylindrical roller = 22/7{21² - (17.5)²} * 200
⇒ Volume of cylindrical roller = 22/7(441 - 306.25) * 200
⇒ Volume of cylindrical roller = 22/7 * 134.75 * 200
⇒ Volume of cylindrical roller = 84700 cm³
Now,
⇒ 1cm³ of iron weighs 8g
⇒ 84700cm³ of iron weighs = (8 * 84700)g
= 677600g
= 677600/1000 kg
= 677.6 kg
Therefore,