Two block of equal mass m are connected by an unstreatched spring and the system is kept at rest on a frictionless horizontal suface. A constant force F is applied on the first block pulling it away from the other as shown in figure.

Then the displacement of the centre of mass at time t is

Options

A. `(Ft^(2))/(2m)`
B. `(Ft^(2))/(3m)`
C. `(Ft^(2))/(4m)`
D. `(Ft^(2))/(m)`

Answer

C

Explanation

As `ma_(cm) = f rArr a_(cm) = (f)/(2m) " so " s_(cm) = (1)/(2) at^(2) = ((f)/(4m))t^(2)`