A rocket is moving in a gravity free space with a constant acceleration of `2 m//s^(2)` along `+ x` direction (see figure). The length of a chamber inside the rocket is `4 m`. A ball is thrown from the left end of the chamber in `+ x` direction with a speed of `0.3 m//s` relative to the rocket . At the same time , another ball is thrown in `+ x` direction with a speed of `0.2 m//s` drom its right end relative to the rocket . The time in seconds when the two balls hit each other is