Answer : The correct option is, 1 hr to 2 hr
Explanation :
Velocity : Velocity is defined as the rate of change of position of an object with respect to the time. It is a vector quantity that means it tell us about the magnitude and direction of an object.
Formula used :
[tex]Velocity=\frac{Displacement}{Time}[/tex]
To calculate the velocity for time interval 0 to 2 hr:
[tex]Velocity=\frac{(15-0)km}{(2-0)hr}=7.5km/hr[/tex]
To calculate the velocity for time interval 2 to 4 hr:
[tex]Velocity=\frac{(20-15)km}{(4-2)hr}=2.5km/hr[/tex]
To calculate the velocity for time interval 4 to 5 hr:
[tex]Velocity=-\frac{(20-0)km}{(5-4)hr}=-20km/hr[/tex]
From this we conclude that, at time interval 0 to 2 hr the motion will be fastest.
Hence, the correct option is, 1 hr to 2 hr
