An electric train is moving with a velocity of $120 \, km \, h^{-1}$. How much distance will it cover in $30 \, s$ (in $, km$)?

Starting from rest,a scooter acquires a velocity of $36 \, km/h$ in $10 \, s$ and then brakes are applied,taking $20 \, s$ to stop. Calculate the acceleration and the total distance travelled.

$A$ body is moving with a velocity of $10 \, m s^{-1}$. If the motion is uniform,what will be its velocity after $10 \, s$ (in $, m s^{-1}$)?

$A$ car manufacturer advertises that the brakes are so perfect that the car stops instantaneously. Comment.

There is an argument about uniform acceleration between $Mr. X$ and $Mr. Y$. $Mr. X$ says,"acceleration means that the farther you go, the faster you go". $Mr. Y$ says,"acceleration means that the longer you go, the faster you go". Whose statement is correct?

$(a)$ 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.