A train travels from station A to station B at a constant speed of 40 km. `h^(-1)` and returns from B to A at 60 km . `h^(-1)` . Find the average speed and average velocity of the train.

Explanation

Let the distance between the stations A and B be x km. Time taken by the train to move from A to B = `(x)/(40)` h and time taken to move from B to A = `(x)/(60)` h.
Total distance travelled = 2 xkm.
`:.` Average speed = `(2x)/(((x)/(40)+(x)/(60)))=(2xx40xx60)/(100)=48 "km".h^(-1)`
Initial and final positions are the same and so the total displacement becomes zero and hence average velocity is zero.