A train is moving slowly on a straightly track with a constant speed of `2 ms^(-1)` . A passenger in the train starts walking at a steady speed of `2 ms^(-1)` to the back of the train in the opposite direction of the motion of the train . So, to an observer standing on the platform directly in the front of that passenger appears to be

Options

A. `4 ms^(-1)`
B. `2 ms^(-1)`
C. `2 ms^(-1)` in the opposite of the train
D. zero

Answer

D