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A wheel which is cylindrical in shape makes 40 revolutions in a minute. The radius of wheel is 3 m and the height is 3.5 m. Find the total area covered by the wheel in making 21 revolutions. (Take π = 22/7)

A wheel which is cylindrical in shape makes 40 revolutions in a minute. The radius of wheel is 3 m and the height is 3.5 m. Find the total area covered by the wheel in making 21 revolutions. (Take π = 22/7) Correct Answer 1,386 m<span style="position: relative; line-height: 0; vertical-align: baseline; top: -0.5em;font-size:10.5px;">2</span>

Given:

Number of revolutions taken by cylindrical wheel = 21

Radius (r) of wheel = 3 m

Height (h) of wheel = 3.5 m

Concepts used:

Curved surface area (CSA) of cylindrical wheel = 2πrh

Calculation:

Curved surface area of wheel = Area covered by wheel in 1 revolution

CSA of wheel = 2πrh

⇒ 2 × 22/7 × 3 × 3.5 m2

⇒ 66 m2

Area covered in 1 revolution = 66 m2

⇒ Area covered in 21 revolutions = 66 × 21 m2 = 1,386 m2

∴ Total area covered by the wheel in making 21 revolutions is 1,386 m2.

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