Question

Two springs A and B(k_A = 2k_B) are stretched by applying forces of equal magnitudes at the four ends. If the energy stored in A is E, that in B is 

(a) E/2 

(b) 2E 

(c) E 

(d) E/4.

Answer 1

(b)  2E.

Explanation:- 

Since (k_A = 2k_B) it means for the same force x_B = 2x_A . So if energy stored in spring A = E = F.x_A   Energy stored in spring B = F.x_B =F.2x_A =2E