Question

First half of a distance is covered with constant speed 5m/s and second jalf with 9m/s .find average speed

Answer 1

Answer:

45/7 m/sec

Explanation:

Let the total distance be 2D

For first half,

speed = distance/time

5=D/time

=> time = D/5

For second half,

speed = distance/time

9=D/time

=> time = D/9

Total time = D/5+D/9= 14D/45

avg. speed = total distance/total time

= (2D)/(14D/45)

= 45/7 m/sec