Two equal masses are attached to the two ends of a spring of spring constant `k`. The masses are pulled a part symmetrically to stretch the spring by a length `x` over its natural length. The work done by the spring on each mass is.

Options

A. `(1)/(2) kx^(2)`
B. `-(1)/(2) kx^(2)`
C. `(1)/(4) kx^(2)`
D. `- (1)/(4) kx^(2)`

Answer

D

Explanation

Work done on both block are the same and total work done by spring is `- (1)/(2) kx^(2)`
Hence on each block `- (1)/(4) kx^(2)`.