A particle accelerates from rest at a constant rate for sometime and attains a constant velocity of $8\, m s ^{-1}$. Afterwards it decelerates with a constant rate and comes to rest. If the total time taken is $4$ second, the distance travelled is

Study the given graph and answer the following questions

$(i)$ Which part of the graph shows accelerated motion ?

$(ii)$ Which part of the graph shows retarded motion ?

$(iii)$ Calculate the distance travelled by the body in first $4$ seconds of journey graphically.

The area under the velocity$-$time graph gives the value of

$(a)$ What is acceleration ? Write its $SI$ unit.

$(b)$ Draw velocity-time graph, when an object has

$(i)$ uniformly accelerated velocity

$(ii)$ uniformly retarded velocity.

Give one example for each of the type of motion when

$(i)$ acceleration is in the direction of motion.

$(ii)$ acceleration is against the direction of motion.

$(iii)$ acceleration is uniform.

"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