Two block-spring mass system are moving on smooth horizontal surface as shown in the figure as t=0. find out the minimum time t when the spring is maximum elongated `l_(0)` is the natural length of spring.

Explanation

`T=2pisqrt((4)/(9pi^(2)))=(2xx2)/(3)=(4)/(3)`
`t=(3T)/(4)=(3)/(4)xx((4)/(3))=1`