Question

The average speed of an object or a given time duration is 6 m/s. if it travels first half of the duration with a constant speed 4m/s, what is its speed during the next half duration?a) 5m/sb) 4m/sc) 6m/sd) 8m/s

Answer 1

Suppose the object takes time t to complete the journey.

It travels for time t/2 at speed 4 m/s. So, the distance travelled in this t/2 is = 4t/2 = 2 t

It travels the next time t/2 at speed v m/s. So, the distance travelled in this t/2 is = v t/2 = v t/2

Now,

Average speed = total distance/total time
(2t+vt/2)/t=6

2+v/2=6
or
v/2=4
or
v=8 m/s