The driver of a train $A$ travelling at a speed of $54\, km h^{-1}$ applies brakes and retards the train uniformly The train stops in $5\, s$. Another train $B$ is travelling on the parallel track with a speed of $36\, km h ^{-1}$. This driver also applies the brakes and the train retards uniformly. The train $B$ stops in $10\, s$. Plot speed time graph for both the trains on the same paper. Also, calculate the distance travelled by each train after the brakes were applied.

"The direction in which an object moves is given by the direction of velocity of the object and not by the direction of acceleration". Give an example to justify this statement

What can you conclude about the motion of a body depicted by the velocity$-$time graphs $(i),(i i)$ and $(i i i)$ given below

Distinguish between terms speed and velocity.

$(a)$ Draw velocity-time graph for the following cases

$(i)$ When the object is at rest.

$(ii)$ When the object is thrown vertically upwards.

$(b)$ A motorcyclist riding motorcycle $A$ who is travelling at $36\, km h^{-1}$ applies the brakes and stops the motorcycle in $10\, s$. Another motorcyclist of motorcycle $B$ who is travelling at $18\, km h^{-1}$ applies the brakes and stops themotorcycle in $20\, s$. Plot speed-time graph for the two motorcycles. Which of the two motorcycles travelled farther before it come to a stop ?