Question

A Roller has a diameter of 0.70 m and its length is 1.5 m. Find the number of revolution it will take to cover an area of a playground whose measure is 50m x 33 m​

Answer 1

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★ A roller has a diameter of 0.70 m and length is 1.5 m . Find the number of revolution it will take to cover an area of a play ground whose measure is 50m × 33m .

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★ Given :

• Diameter = 0.70 m
• length = 1.5 m
• Dimensions of playground = 50m × 33m

★ To Find :

• Number of revolutions = ?

★ Solution :

• Radius =
• $\frac{0.70}{2} m$

Finding The CSA of the roller .

$\rm \: CSA \: = 2 \pi \: rh$

$\rm \mapsto \: CSA \: = \cancel2 \times \frac{22}{ \cancel7} \times \frac{ \cancel{0.70}}{ \cancel2} \times 1.5 \: {m}^{2}$

$\mapsto \rm \: CSA \: = 22 \times 0.10 \times 1.5 \: {m}^{2}$

$\mapsto \boxed{\rm \: CSA \: = 3.3 \: {m}^{2} }$

Now ,

$\rm \star \: no. \: of \: rotations = \frac{area \: of \: playground}{csa \: of \: roller}$

$\rm \mapsto \: no. \: of \: rotations = \dfrac{50 \: \cancel{m} \times \cancel{33} \: \cancel{m}}{ \cancel{3.3} \: \cancel{{m}^{2}} }$

$\mapsto \rm \: no. \: of \: rotation = 50 \times 10$

$\mapsto \boxed{ \rm \: no. \: of \: rotations = 100}$

So ,

It would take 100 rotations to cover the play ground .