The potential energy of a certain spring when stretched through a distance 'S' is `10` joule. The amount of work (in joule) that must be done on this spring to stretch it through an additional distance 'S' will be

Explanation

`P.E.` of spring `U=(1)/(2)Kx^(2)=10J`
When stretched through additional distance `x`,
Total `P.E.` of spring
`U^(')=(1)/(2)K(x=x)^(2)=4xx(1)/(2)Kx^(2)=4xx10J`
`:.` Work done `=U^(')-U=40-10=30J`