For the motion on a straight line path with constant acceleration,the ratio of the magnitude of the displacement to the distance covered is

$(a)$ 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.

Account for the following:
$(a)$ What is the shape of the path of a body when it is in uniform motion?
$(b)$ Give one example of non-uniform motion.
$(c)$ Two cars $A$ and $B$ have their $x-t$ graph as shown in the figure. Which has greater velocity?
$(d)$ What is the quantity which is measured by the area occupied below the velocity-time graph?
$(e)$ $A$ body is moving with a velocity of $10 \, m/s$. If the motion is uniform,what will be the velocity after $10 \, s$?

State whether the following statement is true or false:
In one-dimensional motion,the average velocity and the instantaneous velocity are unequal.

What is the average velocity of a particle when it returns to the starting point? Can its average speed be zero?

Can the speed of a body be negative?