The person stands on the rear end of the roof of a train moving with constant velocity.
The length of the train is 120m.
The man begins to run at this maximum capacity towards the front end, reaches the front end, immediately turns back and runs towards the rear end.
Find the net displacement of the man w.r.t. ground by the time he reaches back to the rear end.
The velocity of the train is 10 m/s.