A rocket is moving in a gravity free space with a constant acceleration of
2 m/s2 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 from its right end relative to the rocket. The time in seconds when the two balls hit each other is