A train is moving in south with a speed of \(90\text{ km/h}.\) The velocity of ground with respect to the train is:

Two parallel rail tracks run north-south. Train \(A\) moves north with a speed of \(54\text{ km/h},\) and train \(B\) moves south with a speed of \(90\text{ km/h}.\) The magnitude of the velocity of \(B\) with respect to \(A\) is:

1. \(40\text{ m/s}\)

2. \(0\text{ m/s}\)

3. \(25\text{ m/s}\)

4. \(15\text{ m/s}\)

A train is moving in the north direction with a speed of \(54\) ${\mathrm{kmh}}^{-1}$. The velocity of a monkey running on the roof of the train against its motion (with a velocity of \(18\) ${\mathrm{kmh}}^{-1}$ with respect to the train) as observed by a man standing on the ground is:
1. \(40\) ms^-1
2. \(0\)
3. \(-5\) ms^-1
4. \(10\) ms^-1