Question

17. A body covers half of its journey with a speed of 50 ms and the other half with a speed of 80
ms-1. What is the average speed during the whole journey?
​

Answer 1

Answer:

Let the total distance be 2x.

For first half distance :

Speed is 20 m/s

Thus time taken t

1

=

20

x

For second half distance :

Speed is 30 m/s

Thus time taken t

2

=

30

x

Average velocity V

avg

=

t

1

+t

2

2x

⟹ V

avg

=

20

x

+

30

x

2x

=

20+30

2×20×30

=24 m/s