An elastic spring of unstretched length L and force constant k is stretched by a small length x. It is further stretched by another small length y. The work done in the second stretching is

An elastic spring of unstretched length L and force constant k is stre

1.	An elastic spring of unstretched length L and force constant k is stretched by a small length x. It is further stretched by another small length y. The work done in the second stretching is
Answer» `1/2 KY^2` `1/2 k(x^2 + y^2)` `1/2 k(x + y)^2` `1/2 ky (2x + y)` Solution :POTENTIAL energy stored in the spring when it is further extended by y is `U_2 = 1/2 k(x + y)^2` `:.`WORK done = `U_2 - U_1 = 1/2 k(x + y)^2 - 1/2 kx^2` `= 1/2 ky (2x + y)`.