The direction of acceleration of an object moving in a circular path is

Explain the following types of motion with one example for each:
$(i)$ Acceleration is positive
$(ii)$ Acceleration is negative
$(iii)$ Acceleration is zero.

Answer the following questions:
$(i)$ State the type of motion shown by a freely falling stone.
$(ii)$ When a stone is thrown vertically upwards,its velocity is continuously decreased. Why?
$(iii)$ Give an example of a motion in which average velocity is zero,but the average speed is not zero.

If the displacement of an object is proportional to the square of time,then the object moves with

Give one similarity and one dissimilarity between the two graphs.

Under what conditions of motion,the distance covered by a body is equal to the magnitude of its displacement?