Question

· A boy goes to market at an average speed of
29 kmh-1. Finding the market closed, he immediately
returns back by the same path with an average speed
of 40 km h-1. Find the (a) average speed (b) average
velocity for the complete journey.​

Answer 1

Explanation:

Distance = s in both case

T1 = s/v1 =s/29 h

T2=s/v2 =s/40 h

A) Av speed for whole trip =total distance /total time

= s+s/t1+t2

=2s km/ s/29+ s/40 h

=2s/69s/1160 km/h

=2× 1160/69 =33.62 km/h

And

B)

Displacement=0

T1=0/29 km/h

T2=0/40 km/h

Average velocity=displacement/time taken

Av=0/0/1160=0km/h because displacement is 0