Question:
Two babies are born in a moving train, one in the compartment adjacent to the engine and the other in the compartment adjacent to the guard. According, to the train frame, the babies are born at the same instant of time. Who is elder according to the ground frame?
Solution:
As frame is in motion $\therefore$ clocks are out of sync. So, if $L^{\prime}$ is length of train in rest and speed of train is $v$ in moving frame then
the clock at one end where guard is standing leads the one near engine by $\frac{\mathrm{cv}}{}$
Therefore, baby born in compartment near guard is elder in comparison with baby born near engine.