Mention the nature of motion of a body if its displacement$-$time graph is a straight line parallel to the time axis.

An aeroplane lands at $216 \ km \ h^{-1}$ and stops after covering a runway of $2 \ km$. Calculate the acceleration and the time in which it comes to rest.

$A$ motorbike running at a speed of $90\, km h^{-1}$ slows down to $18\, km h^{-1}$ in $2.5\, s$. Calculate:
$(i)$ Acceleration
$(ii)$ Distance covered during the deceleration

What is the slope of the displacement $-$ time graph when the body has uniform motion?

$A$ body thrown in the vertically upward direction rises up to a height $h$ and comes back to the position of its start. Calculate: $(a)$ the total distance travelled by the body and $(b)$ the displacement of the body. Under what condition will the magnitude of the displacement be equal to the distance travelled by an object?

State whether the following statement is true or false:
Velocity and speed are measured in different units.