Question

A train moves a distance of 10m with a constant speed of 40m/s and moves the next 5 m with a constant speed of 30 m/s . calculate it's average speed.

Answer 1

Case1:
Distance¹=10m
Speed¹=40m/s
:.Time¹=Distance¹/speed¹
=10/40=1/4s
Case2:
Distance²=5m
Speed²=40m/s
:.Time²=distance²/speed²
=5/30=1/6s
Now,
Total distance=distance¹+distance²
=10+5=15m
Total time=time¹+time²=1/4+1/6=(6+4)/24=10/24=5/12s
Now,
Average Speed=Total distance/total time
=15/5/12m/s
=15×12/5
=3×12=36m/s
(ÆÑẞWĒR)