Question

A cylinder road roller is of lenght 2m and dimeter 84cm find the number of revolution it has to make

Answer 1

H = 2 m

d = 84 cm = 0.84 m

r = 0.42 m

Curved surface area = 2πrh

= 2 × 22/7 × 42/100 × 2

= 5.28 sq. m

Revolutions made = 7920/5.28 = 1500

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Answer 2

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A cylindrical roller is of length 2m and diameter 84cm.find the number of revolutions it has to make to cover an area of 7920meter squared.

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Length of the roller = 2m

Radius

$\frac{84}{2} = 42cm \\ \\ = 0.42m$

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Surface area of cylinder

$2\pi \: rl$

$= 2 \times \pi \times 0.42 \times 2$

$= 5.28 {m}^{2}$

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Number of revolutions

$= \frac{7920}{5.28} \\ \\ = 1500 \: \: revolutions$

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