$\"\"$

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Force required to stretch the spring 30 cm is 250 newtons.

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Therefore $\"\"$ N, $\"\"$ cm.

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Hook $\"\"$ s law: $\"\"$

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Substitute $\"\"$ and $\"\"$ in above formula.

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$\"\"$

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$\"\"$

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Force required to stretch the spring $\"\"$ units is $\"\"$ .

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Substitute $\"\"$ in $\"\"$ .

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$\"\"$ .

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Work done by the object in moving from $\"\"$ to $\"\"$ is $\"\"$ .

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Find work done in stretching the spring from $\"\"$ cm to $\"\"$ cm.

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Here $\"\"$ cm and $\"\"$ cm.

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Substitute $\"\"$ cm , $\"\"$ cm and $\"\"$ in integral formula of work done.

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$\"\"$

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$\"\"$ N-cm.

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$\"\"$ N-m.

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Work done is $\"\"$ N-m.

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$\"\"$

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Work done is $\"\"$ N-m.