Question

A bus covers a distance of 250 km from Delhi to Jaipur towards West in 5 hours in the morning and returns to Delhi in the evening covering the same distance of 250 km in the same time of 5 hours. Find (a) average speed, and (b) average velocity, of the bus for the whole journey.

Answer 1

(i) Average = `("Total distance travelled")/("Total time taken")`
`" "=(250" km"+250" km")/(5" h"+5" h")`
`" "=(500" km")/(10" h")` = 50 km/h
Thus, the average speed of the bus fot the whole journey (both ways) is 50 kilometres per hour.
(ii) In this case, the bus travels 250 km from Delhi to Jaipur towards West and then comes back to starting point Delhi in the reverse direction. So, the total displacement (or total distance travelled in a specified direction) will be 250 km - 250 km = 0 km. Now,
Average velocity = `("Total displacement")/("Total time taken")`
`" "` = `(250"km"-250"km")/(5"h"+5"h") `
`" "=(0 "km")/(10 "h")`
`" "` = 0 km/h
Thus, the average velocity of the bus for the whole journey (both ways) is 0 kilometres per hour. No direction can be stated in this case of zero velocity.