A train transporting military soldiers and supplies during a war is traveling along straight tracks towards a tunnel. When the train is at rest with respect to this particular tunnel, the train and tunnel are moving with the same velocity. What can be said about the relative velocity of the train and tunnel when the train is moving towards the tunnel?
1) The relative velocity of the train and tunnel is zero
2) The relative velocity of the train and tunnel is positive
3) The relative velocity of the train and tunnel is negative
4) The relative velocity of the train and tunnel cannot be determined
