Question

the average speed of an object over a given time duration is 6m/s. If it travels first half of the duration with a constant speed of 4m/s,its speed during the next-half duration is​

Answer 1

Average speed = 6m/s

Let the total distance be 'z'

In first case: It travels first half with, v=4m/s

Therefore, s = z/2  

                  t = s/v = (z/2)m / 4m/s = (z/8)sec.  

So, we know that, v=s/t

                              =>4m/s = (z/2)m / (z/8)sec.

                              =>z=16

Total distance = 16/2 = 8m  ,  Total time = 8/8 = 1 sec.

So, 6 =  8/1+x

 => 6+6x = 8

 => 6x = 2 => x=1/3

In second case : s= 8m

                            t= (1/3)sec.

Therefore, v = s/t => 24m/s