Question

A train leaves New Delhi Railway station at 9:00 a.m. and reaches Jaipur, which is at a distance of 260 km at 12:45p.m..the train reaches Alwar (at distance 150 km from New Delhi) at 11:30 a.m. and stops for 15 minutes. a) What is the reference point for motion of the train? b) What is the average speed of the train between Alwar and Jaipur ?

Answer 1

i) the reference point should be at Delhi because all distance and time are measured from there only.
ii) distance between Alwar and jaipur =260-150=110km
train starts from alwar at 11:45 as it stops for 15 mintues after reaching alwar at 11:30

therefore, time taken by the train to reach jaipur from alwar=12:45-11:45=1hour
average speed of the train= total distance upon total time = 110 divided 1=110km/hr.

Answer 2

I) reference point should be Delhi because all the distance and time is taken from Delhi.
ii) distance from Delhi to Jaipur is 260 km . the distance from Delhi to Alwar is 150 km. so the distance between Jaipur and Alwar is ( 260 - 150) km = 110 km.
iii) time taken from Delhi to Jaipur is 12:45 p.m. .
train stop for 15 mins at Alwar. so time taken by train
to reach to Jaipur is (11:30+0:15) =11:45
The time taken from Delhi to Alwar is 11:30 a.m. .
So, time between Alwar to Jaipur is (12:45 - 11:45) =1 hour.
speed of train is s =d/t
= 110/60 ( because 1 hour is equal to 60 mins)
= 1.83 km/h