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प्रश्न
A roller of diameter 0.9 m and the length 1.8 m is used to press the ground. Find the area of the ground pressed by it in 500 revolutions.
`(pi=3.14)`
उत्तर
Diameter = 0.9 m ∴r = 0.45 m
Height =1.8 m
Number of rotations = 500
Area of the ground pressed by the roller in one rotation = curved surface area of the roller.
= `2pi "rh"`
= 2 × 3.14 × 0.45 × 1.8
= 5.0868 m2
∴ Area of the ground pressed by the roller in 500 rotations.
= 500 × 5.0868 m2
= 2543.4 m2
∴ Area of the ground pressed by the roller is 2543.4 m2
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