Recall that the work of a spring is U12 12 kS22 S12 and ca
     Recall that the work of a spring is U_1-2 = -1/2 k(S_2^2 - S_1^2) and can be either positive or negative. The potential energy of a spring is V = 1/2 ks^2. Its value is  A) always negative  B) either positive or negative  C) always positive  D) an imaginary number 
  
  Solution
Potential energy stored by a spring is considered elastic and given by the equation 1/2kx^2, where x is the extension or compression of the spring. potential energy (Uel) is positive for both positive and negative x values.
 OPTION C

