Give the difference between average speed and average velocity.

The velocity of an object moving in a straight line path is given as a function of time by $v = 6t - 3t^2$,where $v$ is in $m/s$ and $t$ is in $s$. The average velocity of the object between $t = 0$ and $t = 2 \ s$ is

If a car travels $40 \%$ of the total distance with a speed $v_1$ and the remaining distance with a speed $v_2$,then the average speed of the car is:

$A$ car travels from $A$ to $B$ at a speed of $20\,km/hr$ and returns at a speed of $30\,km/hr$. The average speed of the car for the whole journey is............$km/hr$

$A$ boy walks to his school at a distance of $6\, km$ with a constant speed of $2.5\, km/h$ and walks back with a constant speed of $4\, km/h$. His average speed for the round trip,expressed in $km/h$,is:

$A$ body covers the first one-third of the distance with a velocity of $20 \, m/s$,the second one-third with a velocity of $30 \, m/s$,and the last one-third with a velocity of $40 \, m/s$. The average velocity is nearly........$m/s$.