![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b15ab3cd1ae9280c105f80ca8398c710.png\")
where x is the extension of the spring.Step 1:
\The spring has a natural length of 25 cm = 0.25 m.
\Force required to stretch a spring to length of 32 cm is 3.5 N.
\Assume that the spring obeys Hookes law.
\Hooke law : where x is the extension of the spring.
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=903e95de9ad21706a167b8befb003cb3.png\")
Therefore the spring constant is k = 50.
\Step 2:
\Find the work done to stretch a spring of length of 30 cm to 45 cm.
\Work done by the spring : ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=ae625ef17b9d8ac8a3376bdf30909623.png\")
.
Force required in moving an object to a distance of x is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=0017d402a2dbd41a96faca89c15eb40b.png\")
.
Work done to stretch a spring of length of 30 cm to 45 cm.
\Natural length of the spring is 25 cm.
\Now calculate work done to stretch a spring of length of 5 cm to 15 cm.
\![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=4e772923f05ec25a0dcae5c6746a7aee.png\")
Work done to stretch a spring of length of 30 cm to 45 cm is 0.5 J.