State whether the following statement is true or false:
$A$ quantity which can be completely specified by magnitude as well as direction is called a scalar quantity.

The following displacement-time graph shows the positions of a body at different times. Calculate the velocity of the body as it moves from: $(i) A-B, (ii) B-C, (iii) C-D$.

Name a physical quantity that essentially changes as a body moves.

$A$ truck is moving on a straight road with uniform acceleration. The following table gives the speed of the truck at various instants of time.

Speed $(m s^{-1})$	$5$	$10$	$15$	$20$	$25$	$30$
Time $(s)$	$0$	$10$	$20$	$30$	$40$	$50$

Draw the speed-time graph by choosing a convenient scale. Determine from it:
$(i)$ The acceleration of the truck.
$(ii)$ The distance travelled by the truck in $50$ seconds.

$(a)$ Derive graphically the equation for velocity$-$time relation.
$(b)$ Name the device used to measure distance travelled by a vehicle.
$(c)$ Can displacement of a moving object be zero? Give reason.

$(i)$ What can be depicted from the graph regarding the motion of the object?
$(ii)$ Find the value of acceleration from the graph.