An elastic spring of unstretched length `L` and force constant `K` is stretched by amoun t `x` .It is further stretched by another length `y` The work done in the second streaching is

Options

A. `(1)/(2) ky^(2)`
B. `(1)/(2)k(x^(2)+y^(2))`
C. `(1)/(2)k(x+y^(2))`
D. `(1)/(2)ky(2x+y)`

Answer

D

Explanation

`W=(1)/(2)K(x+y)^(2)-(1)/(2)kX^(2)=(1)/(2)ky(2x+y)`