A particle is travelling from point A to point B. These two points are separated by distance D. Assume that the initial velocity of the particle is zero.

Given that the particle never increases its acceleration along its journey, and that the particle arrives at point B with speed V, what is the longest time that the particle can take to arrive at B?

The average velocity is (0+v)/2=V/2 and the time

=D/(AV.VEL.)=**2*D/V**

**This is the time , neither longest nor shortest,**

- the exact time.